explain xkcd - User contributions [en]

563: Fermirotica

2022-06-04T15:55:10Z

141.101.105.35: /* Explanation */

{{comic
| number = 563
| date = April 1, 2009
| title = Fermirotica
| image = fermirotica.png
| titletext = I love how Google handles dimensional analysis. Stats are ballpark and vary wildly based on time of day and whether your mom is in town.
}}

==Explanation==
The {{w|Fermi paradox}} describes the contradiction between the high probability of {{w|extraterrestrial life}} and the lack of empirical evidence thereof. Age and size of the universe suggest that intelligent life should have occurred somewhere, and that some alien civilizations should have developed technology for {{w|interstellar travel}}. Therefore, one might expect the universe full of life. However, no evidence for any lifeforms on other planets has yet been found by humans. This inconsistency was first noted by {{w|Enrico Fermi}} in 1950 when he posed the question "Where is everybody?". The phenomenon, often called ''The Great Silence'', was later examined more thoroughly in a paper by {{w|Michael H. Hart}}.

A decade after Fermi's observation, {{w|Frank Drake}} formulated the {{w|Drake equation}}, which aims at estimating the number of active, communicative extraterrestrial civilizations in the {{w|Milky Way}} galaxy. The formula presents itself as the product of several probabilistic factors which would be required for such a civilization to exist. Several parameters are unknown and the equation assumes that all factors are weighed equally, therefore the equation is not useful for computing any actual result.

The comic presents a somewhat related equation which computes the average distance from the observer wherein a couple can be found copulating. (The example parameters given in the comic yield 139 metres.) The implication of the equation is that we are surrounded by sex in our everyday lives. Nevertheless, we rarely encounter couples during the act itself.{{citation needed}} Borrowing from the Fermi paradox, the ''Fermirotica'' paradox poses the question: "Where is everybody having sex?". Of course, the lack of empirical evidence of couples having sex can easily be explained by the fact that most couples only have intercourse in privacy. A similar approach might also offer an explanation to the original problem: Alien species might conceal themselves from our observations, e.g. in order to {{w|Prime directive|avoid interfering in the development of civilizations}}. This answer to the Fermi Paradox is commonly called {{w|zoo hypothesis}}.

The second panel has [[Cueball]] sexually aroused by the statistical probability of a couple practising intercourse. This fantasy of his is termed ''statistical {{w|voyeurism}}'' by an off-frame speaker, and is evidently upset by it. Possible reasons for being upset are that he considers it an inappropriate use of statistics, or finds voyeurism inappropriate in general, or because it accurately predicts an ''actual'' copulation he is aware of and would rather keep private (e.g. the off-frame speaker is actually about to have sex).

The title text refers to the {{w|Google search#calculator|Google calculator}} and praises its capabilities of {{w|dimensional analysis}}, and more specifically {{w|unit conversion}}. [[Randall]] assumes that most readers will enter the equation with the example parameters into the {{w|Google}} search engine. The built-in calculator will output the result in the correct {{w| SI unit}} ''metre'', although the population density was given as ''people per square mile''. The second part of the title text states that the examples are nothing more than an educated guess, and that the equation is simplified. In reality, more parameters must be taken into account, e.g. the time of day, since most people will have sex in the evening or night. The insulting suggestion that the probability of sex rises when the reader's (supposedly promiscuous) mother is in town represents a ''{{w|Yo Mama joke}}''.

Note that this comic was released on April 1st without being an April Fools' Day comic. But Randall made another April Fool on his reader, see the [[#Trivia|trivia section]].

==Transcript==
:[A formula is shown with the variables explained above:]
:Pd Regional population density (e.g. 18,600/mi²)
:Xf Average person's frequency of sex (e.g. 80/year)
:Xd Average duration of sex (e.g. 30 minutes)
:r=sqrt(2/(π*Pd*Xf*Xd))
:On average, someone within distance r of you is having sex.

:[Cueball standing in front of an easel.]
:Cueball: Mmm, That probable couple 150 meters away is so hot. Oh yeah, theoretically work it, baby.
:From out of frame: Hey! No statistical voyeurism!

==Trivia==
*This comic was released on April 1 with no obvious ties to {{w|April Fools' Day}} and is thus not one of [[Randall|Randall's]], [[:Category:April fools' comics|April fools' comics]].
*But on that day Randall, Jeph Jacques and Ryan North altered their {{w|Domain_Name_System|DNS}} records to point to each others websites. So xkcd.com showed the [http://questionablecontent.net/ Questionable content] website, questionablecontent.net the [http://www.qwantz.com/ Dinosaur comics] website, and www.qwantz.com led to the [http://www.xkcd.com xkcd] website.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Sex]]
[[Category:Math]]
[[Category:Your Mom]]
[[Category:Statistics]]
[[Category:Aliens]]

Talk:2627: Types of Scopes

2022-06-02T21:10:25Z

141.101.105.35:

Wiki's getting hit pretty hard by the trolls this week... [[Special:Contributions/172.69.134.21|172.69.134.21]] 19:02, 1 June 2022 (UTC)
What's with all the vandalism? I know this is the internet, and therefore some vandalism is expected, but YIKES!!! What happened this week? Edit: I don't know who put my message loads, but it wasn't me.[[User:SqueakSquawk4|SqueakSquawk4]] ([[User talk:SqueakSquawk4|talk]]) 19:16, 1 June 2022 (UTC)
:AGREed. waht is the lore behind these schizophrenics and doug walker! holy fuck --[[Special:Contributions/172.70.34.191|172.70.34.191]] 20:07, 1 June 2022 (UTC)
Fixed it. That was annoying [[Special:Contributions/172.70.174.41|172.70.174.41]] 22:15, 1 June 2022 (UTC)

Another spammer appears to be adding comments about their anatomy and disparaging the reader's mother in the explanation of the title text. It has been added and removed at least twice now (once by me), around 22:35. Keep an eye out for small, annoying trolls like this one, as the spammers may have realized that bombarding the pages with massive images is not the cleanest way to ensure they get their (infantile) message across. [[User:Dextrous Fred|Dextrous Fred]] ([[User talk:Dextrous Fred|talk]]) 22:39, 1 June 2022 (UTC)
:There has also been someone who has seen a dislike to Davidy and me... For instance he has created some [https://www.explainxkcd.com/wiki/index.php?title=User:Davidy22,_the_racist_homosexual,_is_known_to_visit_Norwegian_gay_bars_with_his_boyfriend_Kynde._He_has_cheated_on_Kynde_at_least_twice_with_Vandalbane_(a_big_guy_for_you)._They_all_have_micropenises.&action=edit&redlink=1 very long user names]... Must have taken him some time :-D --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:55, 2 June 2022 (UTC)

At least the most obnoxious one seems to be gone (or at least on hiatus). [[Special:Contributions/162.158.107.230|162.158.107.230]] 03:18, 2 June 2022 (UTC)

Randall apparently thinks NPR is the only radio network. It's the only radio I listen too as well. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 13:34, 2 June 2022 (UTC)

Electron Stethoscope would be a cool name for an EIT chest imaging device. [[Special:Contributions/162.158.2.215|162.158.2.215]] 14:28, 2 June 2022 (UTC)

When I first saw the comic title I thought it was going to be about variable scopes in programming. But maybe that would have been too esoteric. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 15:41, 2 June 2022 (UTC)

I was expecting something about sniper scopes (or rifle scopes). Electron sniper scope looks like a thing from Terminator movie. [[Special:Contributions/141.101.105.35|141.101.105.35]] 21:10, 2 June 2022 (UTC)

Data

2022-01-21T10:12:18Z

141.101.105.35: Undo revision 225176 by YRZRyder98 (talk) (spam)

#REDIRECT [[1429: Data]]

2570: Captain Picard Tea Order

2022-01-20T10:28:11Z

141.101.105.35:

{{comic
| number = 2570
| date = January 19, 2022
| title = Captain Picard Tea Order
| image = captain_picard_tea_order.png
| titletext = We can ask the Earl for his order once he's fully extruded from the dispenser.
}}
*This was the fifth comic to come out after the [[Countdown in header text]] started.

==Explanation==
{{incomplete|Created by EXTRUDED EARL GREY- Please change this comment when editing this page. There would be way too many additional [[285: Wikipedian Protester|citations needed]] for it to work here. Do NOT delete this tag too soon.}}

Captain {{w|Jean-Luc Picard}} is the captain of the starship ''USS Enterprise'' in the TV series ''{{w|Star Trek: The Next Generation}}''. {{w|Earl Grey tea}} is a beverage that he requests many times in the series, with the exact phrase "[https://www.youtube.com/watch?v=iaAT6-dY1QI Tea. Earl Grey. Hot.]" Randall is parodying this expression with other words that could follow "Tea. Earl Grey.", from "most normal" to "least normal".

The machine that Picard is using is a {{w|Replicator (Star Trek)|replicator}}, which can create objects, such as Picard's requested Earl Grey tea. The title text refers to the last item, "Tea for him, too." which presumes that the replicator has produced a regular (unspecified) tea and "Earl Grey", a person (either one of the {{w|Earl Grey}}s or a person named Grey with the title of {{w|earl}}), and Picard has requested a tea for him. And so Picard also will ask the Earl for his exact order of tea after he is fully created.

{| border =1 width=100% cellpadding=1 class="wikitable"
! Word !! Explanation
|-
| Hot
| A fairly normal word to be used when ordering tea. Although that it even needs specifying is itself a clue that other variations (such as "Iced", below) are available.
The act of requesting this is illustrated, though not of the appearance of the tea itself.
|-
| Iced
| {{w|Iced Tea}} is a 'normal' variation of tea.
|-
| Decaf
| Traditional teas (from {{w|Camellia sinensis}}) tend to have caffeine in them. Asking for {{w|Decaffeination|decaffeinated}} tea is not particularly uncommon if the drinker requires it.
|-
| Good
| A normal, subjective term. Most people drinking tea would want it to be good, but to specify it like this would perhaps be strange.
|-
| Lukewarm
| While this is a temperature that tea can be at, most people do not want their teas to be lukewarm.
|-
| Tasty
| Similar to good, most people would want their tea to be tasty, or at least flavorsome.
|-
| Boiled
| Boiling the water used to make the tea is a common and normal way to increase the flavor and nutrients extracted from the tea leaves, though it is suggested that the actual ideal temperature of hot water is 75-98°C (167-210°F), according to whether it is a light tea or a dark one, and that perhaps it should be sipped at around 65°C/150°F-ish if desired 'hot'.
Having made a tea and ''then'' bringing it back to the boil (especially after adding milk/etc) may destroy some of the desirable qualities previously imbued.
|-
| Watery
| Tea is a drink that often involves water, but this perhaps suggests over dilution or under infusion in some way.
|-
| Sour
| Many people do not enjoy a sour taste, which can indicate rot and is a strange thing to specify when ordering Earl Grey tea. Although lemon juice is often an additive used in the same way (but as a complete alternative) to milk.
|-
| Meaty
| Most teas are plant-based.
|-
| Solid
| Tea is usually drunk as a liquid. It would be strange to ask for solid tea.
|-
| Dry
| Tea is a liquid typically made with water and may have milk. A dry version might be either unmade (e.g. tea leaves in their un-infused form) or freeze-dried back into a dehydrated form.
("Dry" can also be used to describe {{w|Dryness (taste)|astringent varities of wine}} ''or'' {{w|Prohibition|enforced alcohol-free scenarios}}. For either option, it assumes a default serving with an {{w|Hot_toddy#Variations|alcoholic component}}, or an entirely {{w|Long Island iced tea|alternate basis}} for the beverage, which the request needs to be specify it is not.)
|-
| Raw
| This describes tea that has not been "cooked", so it would just be tea made with room-temperature water. This is {{w|Iced_tea#Sun_tea|possible}} but generally takes many hours.
|-
| Deep-fried
| Tea is not usually deep-fried. But you'll probably {{w|Deep-fried Mars bar|find someone}} who has tried it, [https://www.pitco.com/blog/deep-fried-liquids-trend one way or another].
|-
| Sticky
| Perhaps significantly dehydrated, or thickened with enough of a hydrophilic substance, this would produce something very unlike most teas that would usually be requested.
This scenario is illustrated to show a clearly messy product that awkwardly sticks to and drips from the replicator as well as Picard.
|-
| Grilled
| Tea is not usually grilled.
|-
| Fossilized
| Since tea is a liquid, it would be tricky to figure out how to fossilize it.
|-
| Magnetic
| Tea is not magnetic. Magnetic metals would have to be added to the tea, which would not be pleasant to drink.
|-
| Ballistic
| Usually, the replicated beverage is deposited in a stationary cup, but Picard could ask for it to be dropped or thrown out instead.
|-
| Unstable
| This word is often used to refer to radioactive materials, which hopefully is not a property that would apply to something meant to be ingested. Alternatively, this could imply that the receptacle into which the tea is delivered should be unstable - being unbalanced, or lacking a flat bottom. This is likely to lead to the tea being spilled.
|-
| Blessed
| Tea is a beverage, and it may be strange to ask a machine to create 'blessed' tea.
In role-playing games, items can be Blessed, i.e. having greater positive or lesser negative effects. This includes potions, a class of drinks that do not include any teas but could contain the "potion of water", which may therefore be the basis of this blessed brew.
|-
| Blurry
| Being blurry is not a normal state for tea to have.
|-
| Loud
| While molecules in tea (especially hot tea, and vitally so in an {{w|The Hitchhiker's Guide to the Galaxy (novel)|Infinite Improbability Drive}}) do move vigorously, this does not usually result in distinct audible effects.
However, as illustrated, it seems the requested cup of tea is produced capable of emitting a high-pitched, high-volume whining sound that entirely dominates the vicinity.
|-
| Virtual
| Virtual tea cannot be produced physically, so asking a physical tea machine for it would be very strange.
|-
| Intravenous
| This means the tea would be injected directly into the customer's veins, likely a very painful experience if the tea comes out boiling. Instrument of choice would probably be a {{w|Infuser|''tea infuser''}}.
|-
| Expanding
| In a sense, most hot tea is expanding: as the water in the tea evaporates, it becomes much less dense, increasing in "size".

But most people would probably argue that the evaporated water is no longer part of the tea. Water, like most materials, usually expands as it increases in temperature—except between freezing and about 4° C, where it has the unusual property of {{w|Water_%28molecule%29#Density_of_water_and_ice|''contracting slightly''}} as temperature increases. If tea behaves similarly despite the extra dissolved compounds, then "expanding tea" would describe any tea between 4° C and boiling point. Possibly beyond, and explosively so, if {{w|Superheating|superheated}} and then nucleating points are introduced.
|-
| Ironic
| How tea could be ironic is a mystery.
|-
| Segmented
| Tea is usually served in a cup. It tends to stick together and form one liquid. Separating the tea into segments would not be possible.
|-
| Verbose
| This describes using lots of words and language, and would not likely be used for tea, because it cannot speak. Command-line computer programs often run in a 'silent' mode without displaying every step of what happens on the screen. Such programs may have a {{w|Verbose mode|''-verbose'' parameter}} that disables the silent mode. As the replicator is run by a computer, the verbose parameter could be applied to the process of tea-making, with the replocator providing an info-dump on the molecular arrangement of the tea, together with the cup pf liquid.
|-
| Cursed
| As with "Blessed", above, items can be Cursed in role-playing games, i.e. having greater negative or lesser positive effects; while there are strategic uses for Cursed items, generally the player would prefer uncursed ones (neutral or blessed). Amongst the curseable items are potions, a class of consumables that do not include any teas but does contain the "potion of water", which may therefore be the cause of this cursed cuppa.
Cursed items have featured in xkcd previously: [[2332: Cursed Chair]], [[2376: Curbside]], and [[:Category:Cursed Connectors]].
|-
| Unexpected
| By definition, Picard is asking for tea, expecting it promptly. Perhaps the request for it to be "unexpected" would cause it to be delivered at an unknown time in the future, or to have some alteration.
|-
| Bipedal
| Tea does not walk. This would be a very strange term to use when describing tea.
|-
| Afraid
| Tea does not have feelings. Although [https://www.quotes.net/mquote/901305 water may consider some things to be unpleasant].
|-
| Infinite
| The scope of this request is unclear. It could mean endless production (a steady stream of tea, without obvious limits so long as servicing the request remains practical) or an instantaneous production of an infinite volume of tea (possibly more immediately shown to be flawed in its method of execution). Either could result in an infinitely ''dense'' tea (eventually?), but this may no longer be {{w|No-hair theorem|identifiable as tea}} so might be one of the less practical options, even amongst those on this list.
Indeed, Randall ranks it as the least 'normal', except for just ''one'' further named order.
|-
| Tea for him, too
| {{w|Earl Grey tea|Earl Grey}} is a tea blend.
Taken along with the context of the title text, this Replicator order is for "Tea" (not otherwise qualified), a replicated version ''of'' the Earl Grey (one or other of those {{w|Earl Grey|of that name}}, possibly the {{w|Charles Grey, 2nd Earl Grey|2nd Earl}} for whom the tea blend was supposedly named) and a second such beverage for him to later drink.
|-
! colspan="2" | Descriptions included in comic, but not on the line
|-
| Cold
| Like Iced tea, asking for cold tea is a relatively normal request.
|-
| Pink
| Earl grey is usually an orange-brown color, not pink.
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[There is a line going towards the bottom of the panel in a curve with marks and words next to them. Various pictures of Captain Picard, are displayed next to the curves.]
:[Caption at top of the panel:]
:Other words Captain Picard tried at the end of his tea order before settling on "hot"
:[Subtitle below the caption:]
:From most normal to least
:[Picard stands next to a machine labeled 'REPLICATOR', giving a command. Some options such as 'Good,' 'Cold,' 'Dry,' and 'Pink' are displayed perpendicularly adjacent to 'Hot', the latter clearly selected.]
:Picard: Tea. Earl Grey. Hot.
:[Below, another version of Picard standing next to the replicator is displayed. Picard is holding a cup, with sticky lines connecting his hands and the machine]
:Picard: Tea. Earl Grey. Sticky.
:[This time, Picard is holding a vibrating cup and large letters are displayed in the background to the exclusion of all else.]
:Picard: Tea. Earl Grey. Loud.
:Teacup: '''TEEEEEEEEEEEEEE'''
:[Words on the arrow from start to finish. The tail of the arrow is labeled 'Normal.' There is a parallel arrow pointing in the same direction labeled 'Less normal.']
:Hot
:Iced
:Decaf
:Good
:Lukewarm
:Tasty
:Boiled
:Watery
:Sour
:Meaty
:Solid
:Dry
:Raw
:Deep-fried
:Sticky
:Grilled
:Fossilized
:Magnetic
:Ballistic
:Unstable
:Blessed
:Blurry
:Loud
:Virtual
:Intravenous
:Expanding
:Ironic
:Segmented
:Verbose
:Cursed
:Unexpected
:Bipedal
:Afraid
:Infinite
:Tea for him, too

{{comic discussion}}

[[Category:Star Trek]]
[[Category:Food]]

Header text

2022-01-16T16:54:19Z

141.101.105.35: /* 2020-06-03 - Black Lives Matter */ Typo fix

{{xkcdmeta}}
This page is part of the [[Design of xkcd.com]] explanation.

==Header text==
*The header text is part of the [[Design_of_xkcd.com#Header|xkcd Header]].
*The header text is often [[#Changes to the header text|changing]] when Randall has news to tell.
**But when this news wears off the page usually returns to the '''go-to header text''' which is:
***'''xkcd updates every Monday, Wednesday, and Friday.'''
***It was last changed back to it on [[#2022-01-08 - Back to standard text|2022-01-08]].
****At that time it was almost three years since it last was used.

===Current header text===
*The [[#Changes_to_the_header_text|current header text]] will be the top of the list of changes, if this page is kept up to date...
*Usually the header text is the same for all comics.
**But for certain comics there may be a reason to change the text permanent and as long as that is active they will not change along with the other.
**See [[#Unique header text|Unique header text]]

===Unique header text===
*Some comics have their own version of the header text that do not change.
**Only when the comic is on the front page, will it also be the main header text of xkcd.
**'''Put newest comic at the top.'''
**Here below are examples of that:

====Checkbox====
*[[2445: Checkbox]]
**This comic's header mentions the people who helped put it together.
***It was on the front page from Thursday [https://web.archive.org/web/20210401232108/https://xkcd.com/ 2021-04-01] until Monday [https://web.archive.org/web/20210405130031/http://xkcd.com/ 2021-05-01], until the new comic was released on Monday.
**The text:
***This comic was put together by [https://chromakode.com/ Max Goodhart], [https://twitter.com/fadinginterest Patrick], [https://twitter.com/Aiiane Amber], [https://twitter.com/bstaffin Benjamin Staffin], [https://twitter.com/cotrone Kevin Cotrone], [https://twitter.com/wirehead2501 Kat], and [https://twitter.com/dyfrgi Michael Leuchtenburg].
**It thanks those that helped Randall create that years [[:Category:April fools' comics|April fools' comic]].
***All have a link to their name, the first with a personal home page, the other six with a link to their Twitter account. Five of those also helped with the previous April Fools' comic, see above.
**Since this header was related only to the Fools' comic, it was removed from the front page header, when the next comic was released, here from the day after that release Tuesday [https://web.archive.org/web/20210406143023/http://xkcd.com/ 2021-04-06].
**But it stayed up as one of the permanent different headers on this comic, as seen two days later on [https://web.archive.org/web/20210407203547/https://xkcd.com/2445/ 2021-04-07].

====Collector's Edition====
*[[2288: Collector's Edition]]
**This comic's header mentions the people who helped put it together.
***It was on the front page only for about a day around April 3rd and [https://web.archive.org/web/20200404014814/http://xkcd.com/#-370,-277vApril 4th 2020].
**The text:
***Today's comic was put together by [https://chromakode.com/ Max Goodhart], [https://twitter.com/Aiiane Amber], [https://twitter.com/bstaffin Benjamin Staffin], [https://twitter.com/cotrone Kevin], [https://www.instagram.com/fading_interest/ @fading_interest], [https://twitter.com/wirehead2501 Kat], [https://twitter.com/zigdon @zigdon], and Christopher Night.
****All names have links except the last.
**It thanks those that helped Randall create the 2020 [[:Category:April fools' comics|April fools' comic]], which had taken two extra days before it was released due to the complex nature of the comic.
*Due to the delay the next comic, [[2289: Scenario 4]], was released already the day after the Fool's comic, even though it was thus [[2289:_Scenario_4#Trivia|on a Saturday]]!
**Since this header was related only to the Fools' comic, it was removed from the front page header, when the next comic was released, but it stayed up as one of the permanent different headers on this comic

==== Seven Years====
*[[1928: Seven Years]]
**[http://web.archive.org/web/20171214171157/https://xkcd.com/ 2017-12-14]
**It was released as a response to another cancer diagnosis, this is explained in the [[Design_of_xkcd.com#Header_text|Header text]] which has replaced the standard ''xkcd updates every Monday, Wednesday, and Friday.'' The new one is this one, with the active link included:
**The text (with link):
***Becky Beaton, sister of fellow cartoonist Kate Beaton, has also been diagnosed with cancer. You can support her treatment [https://www.youcaring.com/beckybeaton-1008390 here].
**{{w|Kate Beaton}} is the creator of the web comic [http://www.harkavagrant.com/ Hark! A Vagran].
***Although this comic is not one on Randall's list of ''[[Design_of_xkcd.com#Comics_I_enjoy|Comics I enjoy]]'', he is clearly much influenced by another cancer diagnosis among someone in his own creative field.below.
**On [https://web.archive.org/web/20190817141450/https://www.xkcd.com/1928/ 2019-08-17], close to two years later, the message was still there and also [https://web.archive.org/web/20211226120634/https://xkcd.com/1928/ 2021-12-26] just past four years later.
***There was the possibility that it would be removed, when the support page was discontinued...
***But as that already happened before [http://web.archive.org/web/20181106124430/https://www.youcaring.com/beckybeaton-1008390 2018-11-06] it seems like it will be there to stay.
***Last archived version was from [http://web.archive.org/web/20180305022301/https://www.youcaring.com/beckybeaton-1008390 2018-03-05].
**See the comic on xkcd {{xkcd|1928}}.
*Randall has previously done something similar for another friend, Emiliy, but [[#2014-11-27_-_Help_Emily|that header]] was not made permanent.

====Meteorite Identification====
*[[1723: Meteorite Identification]]
**Randall realized that his comic was almost a copy of some other person. And he has since then acknowledged this on the comics specific page see more [[1723: Meteorite Identification#Trivia|here]].
**At the time of this post, in the newest saved version on the archive from [http://web.archive.org/web/20161010215516/http://xkcd.com/1723/ 2016-10-10] it is still there and says:
***Note: Jolyon, founder of [http://www.mindat.org/ mindat.org], made a similar chart way before me!
**See the comic on xkcd {{xkcd|1723}}.

==== Garden====
*[[1663: Garden]]
**This comic had a header text to help people use the comic when it came out.
**For some time this text was the main header text, but after a while is disappeared from the main header, but remained as the header for Garden.
***See more [[Garden#Header_text_after_release|here]]
**Today and as of the newest saved version on the archive from [http://web.archive.org/web/20161231231600/http://xkcd.com/1663/ 2016-12-31] it is still there and says:
***Protip: If you don't like how your garden is growing, you can click to prune it.
***You can copy the URL to share your garden. From other browsers, it will be view-only.
**See the comic on xkcd {{xkcd|1663}}.

====Money====
*[[980: Money]]
**Randall notes his thoughts about making it and makes a promotion of the poster.
**The unique text for Money is:
***This one was fun (and exhausting) to make.
***There's a poster of it in the [https://store.xkcd.com/products/money-poster store]!
****It is both at the oldest stored version from [https://web.archive.org/web/20120404110059/http://xkcd.com:80/980 2012-04-04] and the newest at time of editing [https://web.archive.org/web/20220108132250/https://xkcd.com/980/ 2022-01-08].

====Na====
*[[851: Na]]
**After Randall made this comic, he realized he could have "made it better" and changed the header text to:
***I can't ''believe'' I forgot Hey Jude.
***I don't get do-overs, but I couldn't resist making [https://xkcd.com/851_make_it_better/ a fixed version].
**See more about it in that comics [[851:_Na#Trivia|trivia section]].
**See the comic on xkcd {{xkcd|851}}.

====House of Pancakes====
*[[472: House of Pancakes]]
**This comic's header notes its status as a parody:
***(Today's comic is a parody of [https://www.amazon.com/House-Leaves-Mark-Z-Danielewski/dp/0375703764 House of Leaves].)
**Only on the days this comic was the newest was this header featured on the front page of xkcd for instance as seen here the day after release on [https://web.archive.org/web/20080906103932/http://www.xkcd.com/ 2008-09-06].
***But it was only on this comic. The commercial for his new t-shirt was on all the other pages, also on [https://web.archive.org/web/20080906103932/http://www.xkcd.com/ 2008-09-06] and presumably returned to the front page with the next comic. But there is a gap in the archive after this comic.
**See the comic on xkcd {{xkcd|472}}.

===Changes to the header text===
*The header text changes often.
**Here these changes can be listed
**Begin with the date of the web archive link and make the date a link.
**Link to the comic that was on the front page when the text changed
**Then describe the changes and put in text if possible
**Also the comic that was the last to feature a message would be interesting to have below the other data.
**Put the newest (current) version at the top.

====2022-01-10 - Standard text with countdown====
*[https://web.archive.org/web/20220110183238/https://xkcd.com/ 2022-01-10].
**[[2565: Latency]] was still up when the [[Countdown in header text]] was added.
**The text was still the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
**But a countdown was added. This was inserted in a rectangular box, placed at the end of the standard header text.
***In some browsers the box forces the last word "Friday" to jump down to the next line.
**Inside the box the following time was displayed in the version in the link:
***20d 20h 27m
****This clock will also count down every minute, although it will return to the time at the time of archive when reloaded!
****While this was edited into this wiki the time had changed to 20d 19h 12m. So it was a very fresh download in the web archive, only about 1 hour old when it was updated to this wiki.
****The minutes change without refreshing the page, and follows this editors computers clock exactly, so it will end at 59 minutes, not at a full hour.
***It looks like it started on [https://munvoseli.github.io/xkcd-countdown/ 01-10 17:00 UTC].
****A calculation shows that this countdown will reach zero on Monday 2022-01-31 at 14:59 (2:59 PM) {{w|UTC}}.
****This will be at 9:59 (9:59 AM) in [[Randall]]'s home town
*****Maybe it will switch to seconds for the last minute to make it switch are 15:00 UTC 10:00 in Boston?
****From that it can be deduced that the count started at 20d 21h 59m
*****The first image on the archive thus came 1h 32m after the count began.
**At [https://web.archive.org/web/20220111153818/https://xkcd.com/ 2022-01-11] a diagonal black bar appeared in the lower left-hand corner of the countdown box.
***After that the [[Countdown in header text]] page was created and any further development on the count down will be mentioned on that page.


====2022-01-08 - Back to standard text====
*[https://web.archive.org/web/20220108044654/https://xkcd.com/ 2022-01-08].
**[[2565: Latency]] came out around the time the new header text appeared, on a Friday!
**The text returned to the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
***This was the first time since [[#2018-11-07 - Back to standard text|2018-11-07]] that the text had changed back to that, and at that time it lasted until 2019-02-05.
***That is 1067 days (less than a month short of three years) without the standard text! (Can it be called standard anymore?)
*It was only left in the complete standard version until [https://web.archive.org/web/20220109030513/https://xkcd.com/ 2022-01-09] when Latencey was still on the front page. Then the next day a [[#2022-01-10 - Standard text with countdown|countdown]] was added to it. That was after the weekend on Monday but before the Monday comic came up. So only during the weekend was it normal standard header text.

====2021-12-20 - What If in stock====
*[https://web.archive.org/web/20211220211220/https://xkcd.com/ 2021-12-20].
**[[2557: Immunity]] came out around the time the new header text appeared.
**The text:
***For anyone trying to find What If? this year, it's in stock at [https://www.barnesandnoble.com/w/what-if-serious-scientific-answers-to-absurd-hypothetical-questions-randall-munroe/1118864093 Barnes & Noble], [https://m.booksamillion.com/p/What-If/Randall-Munroe/9780544272996 Books-a-Million], and [https://bookshop.org/books/what-if-serious-scientific-answers-to-absurd-hypothetical-questions-9781483041827/9780544272996 Bookshop]
**Each store name is a link to the corresponding store's page for [[what if|what if?]].
*It was last seen on [https://web.archive.org/web/20220106100957/https://xkcd.com/ 2022-01-06] when [[2564: Sunshield]] was up.

====2020-06-03 - Black Lives Matter====
*[https://web.archive.org/web/20200604003700/http://xkcd.com/ 2020-06-03].
**[[2315: Eventual Consistency]] came out as a new header text was finally inserted after almost two months without one.
**Cueball is standing to the left and speaks a single line of text: "Black Lives Matter"
**To the right is a gray link button with text: "[https://www.joincampaignzero.org/ How To Help]."
**As always, the entire image (which is only below the xkcd logo) is a link
***The button is thus not needed, but it will also work when clicking the location of the button.
**The link goes to [https://www.joincampaignzero.org/ Join Campaign Zero].
***{{w|Black Lives Matter}} is a loose, grassroots, decentralized confederation of groups and individuals advocating for racial justice. It arose in 2013 after the acquittal of {{w|George Zimmerman}}, who took the life of {{w|Trayvon Martin}}.
***Randall's featuring Black Lives Matter came on the heels of the {{w|Killing of George Floyd}} on May 25th 2020, which had sparked {{w|George Floyd protests|protest in the US}}
***Floyd died while saying "{{w|I can't breathe}}," which was already used due to other Black men's killings, the first was from the {{w|Killing of Eric Garner}}, back in 2014.
*It stayed like this until [https://web.archive.org/web/20200616114945/https://xkcd.com/ 2020-06-16] when [[2320: Millennium Problems]] was up.
**Then on [https://web.archive.org/web/20200617131438/https://xkcd.com/ 2020-06-17] the link changed to [https://blacklivesmatter.com/ Black Lives Matter]. [[2320: Millennium Problems]] was still on the front page on that day.
*On April 1st 2021 the front page header changed to mention who made the April Fools' comic.
**But this was only for this comic [[#Checkbox|Checkbox]].
**The rest of the pages kept the BLM header and it returned to this on the front page once the next comic was released on April 5th. At that time it will have been up for 13 months, making it the longest header different from the standard header.
*It was last up on [https://web.archive.org/web/20211219202204/https://xkcd.com/ 2021-12-19] when [[2556: Turing Complete]] was on the front page.
**At that time it had been up for 564 days or 1,5 year plus 16 days! This is most likely a record.

====2020-04-05 - Empty header====
*[https://web.archive.org/web/20200405042955/https://xkcd.com/ 2020-04-05].
**[[2289: Scenario 4]] came out and the header belonging to the previous comic was removed.
**But no new header was inserted. Not even the go to [[#Header text|Header text]] about the release days of xkcd.
***Since the previous header was related only to the [[:Category:April fools' comics|April fools' comic]] [[2288: Collector's Edition]], and that had stopped the promotion of the [[How To]] book, after first experiencing problems with it's release, it seems Randall forgot what he usually put in the header.
*It stayed empty like this until [https://web.archive.org/web/20200602213017/https://xkcd.com/ 2020-06-02] when [[2314: Carcinization]] was on the front page.
**So almost two month without a header. This had not happened before.

====2020-04-04 - Put together by====
*[https://web.archive.org/web/20200404014814/http://xkcd.com/ 2020-04-04].
**[[2288: Collector's Edition]] came out and the header changed.
**The text:
***Today's comic was put together by [https://chromakode.com/ Max Goodhart], [https://twitter.com/Aiiane Amber], [https://twitter.com/bstaffin Benjamin Staffin], [https://twitter.com/cotrone Kevin], [https://www.instagram.com/fading_interest/ @fading_interest], [https://twitter.com/wirehead2501 Kat], [https://twitter.com/zigdon @zigdon], and Christopher Night.
****All names have links except the last.
**It thanks those that helped Randall create this years [[:Category:April fools' comics|April fools' comic]], which had taken two extra days before it was released due to the complex nature of the comic.
*Due to the delay the next comic, [[2289: Scenario 4]], was released already the day after the Fool's comic, even though it was thus [[2289:_Scenario_4#Trivia|on a Saturday]]!
**Since this header was related only to the Fool's comic, it was thus removed from the general header, but it stayed up as [[#Collector.27s_Edition|one of]] the permanent [[#Unique_header_text|unique header texts]].
***However, when it was removed from the general header, the header was left empty.
***Unlike some other headers that stayed on a given comic, this one was on all comics for the duration of the time it stayed on the front page, see for instance the previous comic on [https://web.archive.org/web/20200403232031/https://xkcd.com/2287/ 2020-04-03].

====2020-04-02 - Technical Reasons====
*[https://web.archive.org/web/20200402234828/https://xkcd.com/ 2020-04-02].
**[[2287: Pathogen Resistance]] was up when the header changed.
*Randall turned out to, again, have problems with his complicated and interactive [[:Category:April fools' comics|April fools' comic]] for 2020.
**The text:
***Note: For technical reasons Wednesday's comic will be posted Thursday instead. Apologies for the delay!
*This finally stopped the promotion of the [[How To]] book.
**It had then been part of the header for well over a year since [http://web.archive.org/web/20190206060904/https://xkcd.com/ 2019-02-06].
*It stayed up a day longer than planed as the fool's comic, [[2288: Collector's Edition]] was first released on Friday, so the note was still up on [https://web.archive.org/web/20200403012612/https://xkcd.com/ 2020-04-03].
**[[2287: Pathogen Resistance]] thus stayed two extra day on the front page, and the third comic of that week, [[2289: Scenario 4]] was released already the day after the Fool's comic, even though it was thus [[2289:_Scenario_4#Trivia|on a Saturday]]!

====2020-01-16 - How To explores - again====
*[https://web.archive.org/web/20200116190038/https://xkcd.com/ 2020-01-16].
**[[2255: Tattoo Ideas]] was still up when the header changed.
**The ongoing promotion of the book continued but here more than three weeks after Christmas the reference to Christmas was removed.
**The header then returned to the one from before Christmas:
***[[#2019-11-22 - How To explores|How To explores]] - see that for all other details.
*It was last up on [https://web.archive.org/web/20200401221435/https://xkcd.com/ 2020-04-01] when [[2287: Pathogen Resistance]] was on the front page.
**It was the problems with [[:Category:April fools' comics|April fools' comic]] of 2020 that finally stopped the promotion of the [[How To]] book.
**It had then been part of the header for well over a year since [http://web.archive.org/web/20190206060904/https://xkcd.com/ 2019-02-06].

====2019-12-02 - Into Science====
*[https://web.archive.org/web/20191202223745/https://xkcd.com/ 2019-12-02].
**[[2236: Is it Christmas?]] came out when the header changed. Fitting as the change is about Christmas list.
**Still promoting the new [[How To]] book, continuing to make the image a link to the [https://xkcd.com/how-to/ How To book] page on xkcd.
***The links below to order are the same as in the previous header.
***Actually most of the header stays the same with the same four images and the same layout. But the text above has changed completely and the two main text sections between the drawings has changed but only slightly. The description of the images is thus left out, see below. Only new thing is that there are now two red circles connected with a red arrow. The first circle is around the word How To at the end of the first text with the arrow going from that circle to the second circle drawn around the picture of the book.
**The text:
***Is there someone on you Christmas list who's into science? They might like my new book '''''How To'''''
***It explores ridiculous ideas for applying scientific research to everyday problems...
***...And illustrates what would happen if you tried them.
***''Boom''
***You can get it here:
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target]
*It was last up on [https://web.archive.org/web/20200115155040/https://xkcd.com/ 2020-01-15] when [[2255: Tattoo Ideas]] was on the front page.

====2019-11-22 - How To explores====
*[https://web.archive.org/web/20191122214439/https://xkcd.com/ 2019-11-22].
**[[2232: Hotel Room Party]] was up when the header changed. It most likely changed when the comic appeared. Earlier on that day it was the previous header over the previous comic.
**Still promoting the new [[How To]] book, here again making the image a link to the [https://xkcd.com/how-to/ How To book] page on xkcd, after it previously was a link to where to listen to the audio book.
***The links below to order returns to the same as in the header before the previous header with links to audio books, except that the link to an exclusive edition has been removed.
***The header consist of an image with text above five small drawings with two text parts in between them. To the left is the closed How To book which is black with a blue readable title, How To, and unreadable white text below this as well as below the unreadable blue author name, which are below the image. The image shows Cueball putting in a light-bulb with drones under each foot while Megan, holding a ladder, and White/Black Hat are looking up at him. To the right of the book is a drawing of Ponytail pole-vaulting with two black helium filled balloons. Next to her is the first text segment. Then after that is the drawing, seen before in the header text, of a truck towing a house up a steep hill. This truck goes above the second text segment, with Cueball somersaulting above the text. Furthest right, above and just right of the text is an explosion with the sound written inside. Below the header image is some black text and then the links to where to get it as regular blue link text.
**The text:
***My new book '''''How To''''' explores the science behind spacecraft heat shields, butterfly metabolisms, and land border surveys...
***...By imagining ridiculous ideas for applying the research to you everyday life...
***...And illustrating what would happen if you tried them.
***''Boom''
***You can get it here:
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target]
*It was last up on [https://web.archive.org/web/20191201191025/https://xkcd.com/ 2019-12-01] when [[2235: Group Chat Rules]] was on the front page.

====2019-11-06 - Audio clip====
*[https://web.archive.org/web/20191106204314/https://xkcd.com/ 2019-11-06].
**[[2224: Software Updates]] was still up when the header changed, but the first archive version was first from after the next comic came out [[2225: Voting Referendum]].
**Still promoting the new [[How To]] book, here making the image a link to the How To book on Penguin Random House's audio book, where a audit clip read by Wil Wheaton can be sampled.
***The links below to order have now changed to those with audio books.
***The header consist of an image with text, with a "blue link", above the How To book that is being folded out from closed; to partially open; to opened up on two full pages; this takes three images. The closed book is the black book with a blue readable title, How To, and unreadable white text below this as well as below the unreadable blue author name, which are below the image. The image shows Cueball putting in a light-bulb with drones under each foot while Megan, holding a ladder, and White/Black Hat are looking up at him. The partly open book still has this cover partly visible, but unreadable, as well as come unreadable text in the open side. The open book shows two pages with lots of unreadable text and three figures (maybe one is a table). Next to the open book there is an arrow to the right pointing at an audio icon with three audio lines in front. Below the header image are the links as regular text.
**The text:
***You can click here to hear a clip from the audio version of '''''How To''''', read by Wil Wheaton.
***[https://books.apple.com/us/audiobook/how-to-absurd-scientific-advice-for-common-real-world/id1475319694 Apple], [https://www.audiobooks.com/audiobook/how-to-absurd-scientific-advice-for-common-real-world-problems/369279 Audiobooks], [https://www.audible.co.uk/pd/How-To-Audiobook/1473680360?qid=1574679523&sr=1-1&pf_rd_p=c6e316b8-14da-418d-8f91-b3cad83c5183&pf_rd_r=DX3EZ14M14CFQPP9GHJY&ref=a_search_c3_lProduct_1_1 Audible], [https://play.google.com/store/books/details/Randall_Munroe_How_To?id=LzSGDwAAQBAJ Google Play], and [https://libro.fm/audiobooks/9780525635680 Libro.fm]
**The entire image is a link to the [https://www.penguinrandomhouseaudio.com/book/576760/how-to/ How To book on Penguin Random House] page, where the audio clip can he played.
***As always it is the entire picture that is a link, and not only the blue underlined text that says click here!
*It was last on the archive on [https://web.archive.org/web/20191122044456/https://xkcd.com/ 2019-11-22] when [[2231: the Time Before And After Land]] was on the front page. But it was most likely still up when [[2232: Hotel Room Party]] came out. But then changed during the next day.

====2019-10-02 - Horse vs football team====
*[https://web.archive.org/web/20191002005854/https://xkcd.com/ 2019-10-02].
**[[2210: College Athletes]] was up when the header changed.
**Still promoting the new [[How To]] book, but seeing this is no longer close to the release day the focus has changed. This time the image seems to be from one of the How To explanations in the book.
***The links below to order are the same as the previous header.
***But new text is added after the links to promote two events with Randall in New York the two days after this header came up.
****These links disappeared after a week leaving only the picture and the link to buy the book. See below.
***The header consist of an image with Cueball riding bareback on a horse. He comes from the left holding an American football. Running towards him from the right are eight American football players with helmets with three stars on the back of the helmet. Two of the players at the back are almost hidden by players in front of them. Beneath them is a line of text that belongs to the image, the period at the end of the sentence hangs in height with the center line of the last letter E... Then below the image follows the link and promotion of the NY events, these are written in regular.
**The text:
***My new book ''How To'' is out now! You can get it here.
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [https://www.barnesandnoble.com/w/how-to-randall-munroe/1130494832?ean=9780525686910#/ B&N Exclusive Edition], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target] I'll be at New York Comic Con! I'm giving [https://www.newyorkcomiccon.com/Explore/Panels/Panels-And-Screenings/#/event/how-todo-anything-with-randall-munroe-creator-of-xkcd a talk on Thursday], and on
***Friday [https://smbc-comics.com/ Zach Weinersmith] and I will be hosting [https://www.caveat.nyc/event/how-to--absurd-scientific-advice-for-common-real-world-problems-10-4-2019 an event at Caveat NYC].
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
***The link to Target still seems to go the main page rather than to [https://intl.target.com/p/how-to-by-randall-munroe-hardcover/-/A-76508342 their How To book page]... Probably a still undiscovered error on Randall's part?
*This header changed, but so slightly that the changes will only be mentioned here rather than in a new section:
**The first link was last active on [https://web.archive.org/web/20191004014438/https://xkcd.com/ 2019-10-04]
**Then the day after only the second link remained from [https://web.archive.org/web/20191005041539/https://www.xkcd.com/ 2019-10-05]. [[2211: Hours Before Departure]] came out when it changed.
***But the text of this link changed as it had been a continues text from one to the other link. Also it was not entirely on it's own line, thus not as with the first link whose text was directly connected to the line with the links to buy the book.
***The new text of that link was:
****[https://smbc-comics.com/ Zach Weinersmith] and I will be hosting [https://www.caveat.nyc/event/how-to--absurd-scientific-advice-for-common-real-world-problems-10-4-2019 an event] Friday night at Caveat NYC!
****The last link was the same, but now it only covered two words not the entire end of the sentence.
***This other link was last active on [https://web.archive.org/web/20191007042707/https://xkcd.com/ 2019-10-07].
**And then the last link was gone by [https://web.archive.org/web/20191008053609/https://xkcd.com/ 2019-10-08], when [[2212: Cell Phone Functions]] came out.
*It ended on [https://web.archive.org/web/20191105164001/https://xkcd.com/ 2019-11-05] when [[2224: Software Updates]] was up.

====2019-09-30 - Tons of fun====
*[https://web.archive.org/web/20190930234245/https://xkcd.com/ 2019-09-30].
**[[2209: Fresh Pears]] was up when the header changed.
**Still promoting the new [[How To]] book, but seeing this is no longer close to the release day the focus has changed to how much fun it was for Randall to write it and how proud he is of the result. Randall, as Cueball, is saying this in the new header image.
***The links below to order are the same, except a new has been added at the end.
***The header consist of an image with Cueball standing to the left of the book, shown as tall as he is. The book is opened up on two pages with lots of unreadable text as well as three drawings, only one of these, with a circle diagram, can clearly be seen. Cueball is speaking, and the text is above him and the book. Two words are blue with a line under as if they where a link. But as always the entire image is a link. Beneath the image is the links on where to order the book.
**The text:
***Writing my new book '''''How To''''' was tons of fun and I'm so proud of the result. It's out now-Click Here to order!
***Order: [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [https://www.barnesandnoble.com/w/how-to-randall-munroe/1130494832?ean=9780525686910#/ B&N Exclusive Edition], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target]
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
***The new link to Target seems to go the main page rather than to [https://intl.target.com/p/how-to-by-randall-munroe-hardcover/-/A-76508342 their How To book page]... Probably an error on Randall's part.
*It ended on October 2nd while [[2210: College Athletes]] where up. But there is no archived versions from the 1st of October and the one from the 2nd is with the next version. But the editor of this was making changes the the explanation of College Athletes before the next header change came along.

====2019-09-11 - How To available====
*[https://web.archive.org/web/20190911053115/https://xkcd.com/ 2019-09-11].
**[[2200: Unreachable State]] was still up when the header changed.
**The release day part of the promotion was changed to telling that the new [[How To]] book was available. With teasers about what is in the book below the heading. On either side of the text a picture of the book is still shown. Also the links below changed, adding three new and removing one old.
***The header consist of an image with the book shown both left and right of some text. Both books have blue title and author name, and white unreadable title and white drawing of Cueball flying on two quadcopters to put in a light-bulb in a ceiling lamp, while White/Black? Hat is watching together with Megan, who is holding a ladder. Beneath the image is the links on where to order it.
***Between the two books are two sections of text above each other, the lover with smaller font.
**The text:
***How To is available now!
***Learn how to open bottles with nuclear weapons and how to be on time for meetings by altering the Earths rotation. The book also features advice from real-life experts including Chris Hadfield and Serena Williams.
***Order: [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [https://www.barnesandnoble.com/w/how-to-randall-munroe/1130494832?ean=9780525686910#/ B&N Exclusive Edition], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible]
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
**{{w|Serena Williams}} is a famous tennis player who was also featured in one of the [[:Category:Book promotion|promotion comics]] for How To: [[2190: Serena Versus the Drones]]
**{{w|Chris Hadfield}} is a Canadian retired astronaut, engineer, and former Royal Canadian Air Force fighter pilot. The first Canadian to walk in space, Hadfield has flown two Space Shuttle missions and served as commander of the International Space Station.
***The new link to audible probably needs the user to be signed up, else it will go the the front page and ask yo to sign up. But from the archive the page can be seen [https://web.archive.org/web/20190923004816/https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 here].
*Up till [https://web.archive.org/web/20190922143253/https://xkcd.com/ 2019-09-22] it looked like this.
**Then on [https://web.archive.org/web/20190923145251/https://xkcd.com/ 2019-09-23] and extra link was added after Audible:
***[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target].
**[[2205: Types of Approximation]] was up when this change occurred during a weekend.
*It ended on [https://web.archive.org/web/20190929223547/https://xkcd.com/ 2019-09-29] when [[2208: Drone Fishing]] was up.

====2019-09-04 - Happy Release Day - bookstore====
*[https://web.archive.org/web/20190904051509/https://xkcd.com/ 2019-09-04].
**[[2198: Throw]] was already up when the header changed slightly, as the text below Happy release day changed.
*Most of the header stayed the same as the [[#2019-09-03 - Happy Release Day - calender|day before]], but the reference to the Gregorian/Julian calender was changed.
**The header consist of an image with the book shown both left and right of some text.Both books have blue title and author name, and white unreadable title and white drawing of Cueball flowing on two quadcopters to put in a light-bulb in a ceiling lamp, while White/Black? Hat is watching together with Megan comes who is holding a ladder. Beneath the image is the link on where to order it, now the preorder has been changed to order.
***Between the two books are two sections of text above each other, the lover with smaller font and in brackets.
**The text:
***Happy How To release day!
***Available wherever books are sold.
***(Mostly bookstores, I assume but you can always try your luck at Wendy's.)
**See below for any other details.
*It ended on [https://web.archive.org/web/20190909211737/https://xkcd.com/ 2019-09-09] when [[2200: Unreachable State]] was up.

====2019-09-03 - Happy Release Day - calendar====
*[https://web.archive.org/web/20190903051503/https://xkcd.com/ 2019-09-03]
**[[2197: Game Show]] was still up when the header changed, but it was for sure to coincide with [[2198: Throw]] which came out later on the release day while it still looked like in this version.
**Randall celebrated the release day of [[How To]], coming out the day the header changed.
***The comic is also a reference to a chapter in the book on how to throw things. A very complicated interactive comic where different persons or other living things can be chosen to throw dead or living things. The trow will then be shown below with distance measured in two units, normal and special. That is if the thrower can actually manage to throw the thing.
**The header consist of an image with the book shown both left and right of some text. The two black books have red stars around them, five on the outer side of the image and 6 on the inner, the stars are mirrored around left and right book. Both books have blue title and author name, and white unreadable title and white drawing of Cueball flying on two quadcopters to put in a light-bulb in a ceiling lamp, while White/Black? Hat is watching together with Megan, who is holding a ladder. Beneath the image is the link on where to order it, now the preorder has been changed to order.
***Between the two books are two sections of text above each other, the lover with smaller font and in brackets.
**The text:
***How To Randall Munroe
***Happy How To release day!*
***(*Gregorian calendar. The Julian edition doesn't come out for 13 more days.)
***How To Randall Munroe
***Order: [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
**Most of the world uses the {{w|Gregorian calendar}}, but before it was taken into use, the {{w|Julian calendar}} was in use.
***The Julian calendar does not take into account that every 100 years a leap year should be passed as in the Gregorian calendar, and thus it is at the moment 13 days behind, as it has has this many February 29th too many. Since there should actually be a leap year every 400 year, and the last of those was 2000, then it has been 13 days since 1900, and will stay like this until 2100 when it will become 14 days.
***The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
**Already the next day the part of the header below happy release day about the Gregorian calender changed. See [[#2019-09-04 - Happy Release Day - bookstore|above]].

====2019-08-27 - Out in a week====
*[https://web.archive.org/web/20190827082224/https://xkcd.com/ 2019-08-27].
**[[2194: How to Send a File]] was up when the header changed.
**Randall continues to promote his new book, [[How To]], coming out a week from this header.
***It is only three lines of text
**The text:
***My new book, How To, comes out next week!
***Read an exclusive excerpt about transmission [https://blog.xkcd.com/2019/08/26/how-to-send-a-file/ here].
***[Four links in gray blue are given with the first words in black:] Preorder ''How To'': [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
**Later [https://web.archive.org/web/20190827184229/https://xkcd.com/2194/ on the same day], (and here for the next day [https://web.archive.org/web/20190828095401/https://xkcd.com/ 2019-08-27] for the front page), more text and links where added, plus the order of the text was changed.
**The later text was:
***My new book, [https://xkcd.com/how-to/ How To], comes out in a week! ([https://blog.xkcd.com/2019/08/23/book-tour-and-contest-winner/ Book tour info])
***You can preorder it now to get a copy when it's released:
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
***You can also read an exclusive excerpt about file transfers [https://blog.xkcd.com/2019/08/26/how-to-send-a-file/ here].
**The link to the book tour also include the winner of the [[#2019-06-25 - People with books|contest]] to get Randall to add "your" city to his book tour.
***The winner was {{w|Juneau, Alaska}}.
*It ended on the release day 2019-09-03, so this was last on the page on [https://web.archive.org/web/20190902042108/https://xkcd.com/ 2019-09-02].

====2019-08-06 - Win a sketch====
*[http://web.archive.org/web/20190806052948/https://xkcd.com/ 2019-08-06].
**[[2185: Cumulonimbus]] was up when the header changed.
***Most likely the header changed when that comic came out on 2019-08-05. But the previous header was also out during that day.
**Randall continues to promote his new book, [[How To]], now making a competition where you can win a stick figure sketch of yourself. (Although only for US residents!)
***The image shows Hairy, with a cat at his feet and Megan (or Danish?) with a samurai sword. They are standing with their backs towards each other, the cat on the left, Megan facing right with the sword towards the words.
***Below the drawing are links to places to preorder the book.
**The text:
***Want to win a sketch of yourself as a stick figure? [https://blog.xkcd.com/2019/08/05/win-an-xkcd-sketch/ Click here] to find out how!
***[Four links in gray blue are given with the first words in black:] Preorder ''How To'': [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
****The entire picture is a [https://blog.xkcd.com/2019/08/05/win-an-xkcd-sketch/ link] to a [[Blag]] post: ''Win an xkcd sketch''
****That is even though only the click here part of the text is in blue, like a link.
****Cause as he often has written: I still haven't figured out HTML imagemaps, most recently in the [[#2019-07-09 - Drawings from How To|2019-07-09]] header.
*The header stayed like this until [https://web.archive.org/web/20190826062701/https://www.xkcd.com/ 2019-08-26] when [[2193: Well-Ordering Principle]] was up.

====2019-08-03 - First look inside====
*[http://web.archive.org/web/20190803222711/https://xkcd.com/ 2019-08-03].
**[[2184: Unpopular Opinions]] was up when the header changed.
**Randall continues to promote his new book, [[How To]], now stating that it comes out next month.
***Set to be released on September 3rd 2019, this update was made exactly one month before.
***The image shows text to the left of three drawings of the book: First the closed book showing the black front cover with blue and white text and white drawings, then the book is partly opened, and finally it lays opened up showing two pages, with a readable heading on the right page.
***Below the drawing are links to places to preorder the book.
**The text:
***My new book comes out next month. Click here for a first look inside!
***[On the books front cover only two thins can be read:]
****How To
****Randal Munroe.
***[These two words can also partly be read on the opening book.]
***[Only the large heading can be read on the right page of the open book:]
****How to Dig a Hole.
***[These two pages also became part of a special comic relased during the weekend when this header was up: [[Disappearing Sunday Update]].]
***[The [[Disappearing_Sunday_Update#Transcript|transcript of that comic]] describes the images in the open book.]
***[Four links in gray blue are given with the first word in black:] Preorder:[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
****The entire picture is a [https://blog.xkcd.com/2019/08/02/how-to-chapter-list-and-introduction/ link] to a [[Blag]] post: ''How To: Chapter list and introduction''.
*It stayed up like this while the special [[Disappearing Sunday Update]] came out on Sunday 2019-08-04, and was there still on Monday [ http://web.archive.org/web/20190805050812/https://www.xkcd.com/ 2019-08-05], at least during the time that the Sudan Update was still up.
**When the next comic came out late that Monday, it probably disappeared along with the Disappearing comic, but the first update with the next header is from Tuesday [http://web.archive.org/web/20190806052948/https://xkcd.com/ 2019-08-06], but the Monday comic [[2185: Cumulonimbus]] was still on the front page at that time,.

====2019-07-23 - Back to previous header====
*[http://web.archive.org/web/20190723205152/https://xkcd.com/ 2019-07-23].
**[[2179: NWS Warnings]] was up when the header changed.
*It returned to the previous header from before the ComicCon header, see [[#2019-07-10 - Adding links|2019-07-10]]
*It stayed up until [http://web.archive.org/web/20190802192259/https://xkcd.com/ 2019-08-02] while [[2184: Unpopular Opinions]] was up. The day after when it changed that comic was still up.

====2019-07-15 - ComiCon====
*[http://web.archive.org/web/20190715181016/http://xkcd.com/ 2019-07-15].
**[[2176: How Hacking Works]] was up when the header changed.
*Randall tells that he will be at ComicCon and links to his plans there.
**The text:
***Going to San Diego Comic Con this week? I'll [https://blog.xkcd.com/2019/07/15/san-diego-comic-con/ see you there]!
****The link is to a [[Blag]] post about his plans for the ComicCon
**Randall appeared in a couple of panels, and gave a talk.
**Finally he also handed out signed copies of his new [[How To]] book more than a month before official release.
***So still promoting the book, also in this header...
*It stayed up until [http://web.archive.org/web/20190722192637/https://www.xkcd.com/ 2019-07-22] the day after the ComiCon ended, while [[2178: Expiration Date High Score]] was up.
**Then it returned to the previous header from before the ComicCon announcement when [[2179: NWS Warnings]] came out.

====2019-07-10 - Adding links====
*[http://web.archive.org/web/20190710165920/https://xkcd.com/ 2019-07-10].
**[[2173: Trained a Neural Net]] was still up when the header changed slightly from that fro the day before.
**Only change was that beneath the picture, see [[#2019-07-09 - Drawings from How To|2019-07-09]], there is now a list of four links to companies where the book can be preordered.
**The extra text:
***[Four links in gray blue are given with the first word in black:] Preorder:[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
*Note that the day after this change, [https://web.archive.org/web/20190711172451/https://xkcd.com/ 2019-07-11], a link to [[How To]] was added to the [[Design_of_xkcd.com#xkcd_links|links]] in the top left corner of xkcd.
*The header stayed like this until [http://web.archive.org/web/20190714175710/https://xkcd.com/ 2019-07-14] when [[2175: Flag Interpretation]] was up. When it changed the day after [[2176: How Hacking Works]] was up.

====2019-07-09 - Drawings from How To====
*[http://web.archive.org/web/20190709162102/https://xkcd.com/ 2019-07-09].
**[[2173: Trained a Neural Net]] was up when the header changed.
**Randall continues to promote his new book, [[How To]].
***The image shows a small picture of his book with text on either side.
***Below are what appears to be three drawings from the book. [[Ponytail]] pole vaultig with three baloons in one hand, then text, then a truck with a house behind it speeding fast up a hill then text and finally [[Cueball]] somersaulting towards an explosion.
***To the right there is a big blue button to click for preorder, with text below.
**The text:
***New book [Arrow points to book. Title can be read: How To]
***How To: Absurd Scientific Answers to Common Real-world Problems
***It's a guide to bad ways to do things...
***...And what would happen if you tried them.
***''Boom''
***Click here to preorder
***Or click anywhere. I still haven't figured out HTML imagemaps.
****The entire picture is a [https://xkcd.com/how-to/ link] to the official [[How To]] page on xkcd: https://xkcd.com/how-to/
****See [[1572: xkcd Survey]] where Randall mentions that he cannot make imagemaps.
*It stayed up like this only for a day, then an extra line of links was added the day after while the same comic was still up, see [[#2019-07-10 - Adding links|2019-07-10]].
**But the general header stayed up first for five days, and then it returned again for 10 more days after a break to announce a [[#2019-07-15 - ComiCon|ComiCon visit]].
**So a total of 16 days with this drawing.

====2019-06-25 - People with books====
*[http://web.archive.org/web/20190625190843/https://xkcd.com/ 2019-06-25].
**[[2167: Motivated Reasoning Olympics]] was up when the header changed.
**Randall continues to promote his new book, [[How To]], and his book tour.
***The image now shows 15 people standing side by side each holding a book up in front of them with unreadable titles.
***From left: [[Megan]], [[Cueball]], a man with blonde hair, [[Science Girl]], [[Blondie]], [[Hairy]], another Hairy, [[White Hat]], a kid with curly hair, [[Hairbun]], another Cueball, another Megan, a guy with a knit cap, [[Ponytail]] and [[Beret Guy]].
***Above them is a text message.
**The text:
***Want to bring me to your town for my '''''How To''''' book tour? Click to find out how to enter the challenge!
****The entire picture is a [https://blog.xkcd.com/2019/06/10/book-tour-announcement/ link] to the official book tour announcement posted on the [[Blag]], with all cities and dates listed with details.
****In the link it is explained how to enter a competition on how to bring Randall to your city.
****Make a story using only book titles and get the books used to be held up by different individuals.
****A longer sentence will improve your chances.
*****This is indeed what this header picture shows.
*The header stayed like this until [http://web.archive.org/web/20190708155517/https://xkcd.com/ 2019-07-08] when [[2172: Lunar Cycles]] was up. When it changed the day after [[2173: Trained a Neural Net]] was up.

====2019-06-15 - Adding dates====
*[http://web.archive.org/web/20190615100645/http://xkcd.com/ 2019-06-15]
**[[2163: Chernobyl]] was up when the header changed.
**Randall only made a small change to the one that had been up for four days at this time.
**The text only changed by adding a line below the first line:
***Announcing the '''''How To''''' book tour:
***[Click here for dates and tickets]
****The rest of the header is exactly the same as on [[#2019-06-11 - Book tour|2019-06-11]], except everything is a bit smaller to make room in the same place for the extra line.
****The link is not located on the blue part of the text and it was already there before this update.
****Best guess is that not many clicked through and Randall then made it obvious that there was a link.
****The entire picture is a [https://blog.xkcd.com/2019/06/10/book-tour-announcement/ link] to the official book tour announcement posted on the [[Blag]], with all cities and dates listed with details.
****Randall has previously made it clear, in [[1572: xkcd Survey]], that he knows how to make an image a link, but not how to put the link only where he says to click. But it is easier to make a place for people to click than tell them this...
*The header stayed like this until 2019-06-25, when it changed while [[2167: Motivated Reasoning Olympics]] was up. But this one was still up when that comic came out the day before [http://web.archive.org/web/20190624162740/https://xkcd.com/ 2019-06-24].

====2019-06-11 - Book tour====
*[http://web.archive.org/web/20190611031920/https://xkcd.com/ 2019-06-11]
**[[2161: An Apple a Day]] was up when the header changed.
***'''Note''' when this change happened two new links was added to the [[Design_of_xkcd.com#xkcd_links|xkcd links]] section of xkcd.
**Randall changed the header text to announce the official book tour for his newest book ''[[How To]]'' to be released 3 months later.
**The text:
***Announcing the '''''How To''''' book tour:
***[Below this header is a map of the mainland USA with 14 labeled black dots indicates the 14 cities that the book tour will take Randall to. One red dot with five red question marks above is located beneath the map to the left, indicating a 15th city to be chosen in a contest. Above the map to the right is a small picture of the book with the blue title on the black cover. Above the book is the release date and with an arrow pointing down to the book.]
***September 3rd
***How to
***Seattle
***Portland
***San Francisco
***Santa Cruz
***Los Angeles
***Salt Lake City
***Kansas City
***Ann Arbor
***Cincinnati
***Louisville
***Cambridge
***New York
***D.C.
***Raleigh
***????? (Chosen by readers)
***[The entire picture is a [https://blog.xkcd.com/2019/06/10/book-tour-announcement/ link] to the official book tour announcement posted on the [[Blag]], with all cities and dates listed with details.]
****In the link it is explained how to enter a competition on how to bring Randall to your city.
****Make a story using only book titles and get the books used to be held up by different individuals.
****Only US cities can apply.
**The header only stayed exactly like this for three days, and was still up on [http://web.archive.org/web/20190614094729/https://xkcd.com/ 2019-06-14] when [[2162: Literary Opinions]] was on the front page.
***Then it changed slightly to indicate that the picture was a link which was not clear before. See above.

====2019-05-17 - Back to previous header====
*[http://web.archive.org/web/20190517103928/https://xkcd.com/ 2019-05-17]:
**[[2150: XKeyboarCD]] was still up when the header changed.
*It changed back to the exact same heading as before the one with Google reader here below.
**See [[#2019-02-06 - How to book|2019-02-06]] below for all details.
**It stayed up for more than three weeks and was still up on [http://web.archive.org/web/20190610055519/https://www.xkcd.com/ 2019-06-10], while [[2160: Ken Burns Theory]] was still up on the day the next comic [[2161: An Apple a Day]] was to be released (where the new header could be found at least the next day, but maybe from the release of that comic?). Then it changed to announce the book tour for his new book.

====2019-04-23 - Google Reader====
*[http://web.archive.org/web/20190423155458/https://xkcd.com/ 2019-04-23]:
**[[2140: Reinvent the Wheel]] came out when it changed, ending a more than two and half month long [[#2019-02-06 - How to book|promotion]] of Randall's new book [[How To]].
**Randall changed the header text to ask if the reader still mourned the loss of {{w|Google Reader}} which closed on 2013-07-01, almost 6 years before this comic..
***He offers the possibility to sign up to receive the newest comic by e-mail.
**The comic may have relation to this, as some where using Google reader for different purposes when they closed it, without any chance of [https://www.google.com/reader/about/ getting your data out].
***The comic "Reinvent the Wheel" mentions that using external dependencies carry risks, such as Google closing down a feature. given the fact that the comic came out as the header changed it is probably not a coincidence.
**The text:
***Still mourning the demise of Google Reader? You can sign up to get new comics delivered by email [https://xkcd.com/newsletter/ here].
**The link is to https://xkcd.com/newsletter, where it is possible to submit your e-mail address and press a subscribe button.
***the following text is written above it:
***To receive the comic and news postings in your inbox, subscribe here.
**It stayed up for more than three weeks and was still up on [http://web.archive.org/web/20190516100403/https://xkcd.com/ 2019-05-16], when [[2150: XKeyboarCD]] was up. Then it changed back to the promotion of his new book.

====2019-02-06 - How to book====
*[http://web.archive.org/web/20190206060904/https://xkcd.com/ 2019-02-06]:
**[[2107: Launch Risk]] was up at the time when it changed, having been up since Monday the 4th of February.
***Here it can be seen being on the front of xkcd on [http://web.archive.org/web/20190205050302/https://xkcd.com/ 2019-02-05], without the new text. This was also the last time the standard header text was used in several months.
***[[2108: Carbonated Beverage Language Map]] came up later on the day the header changed.
**Randall changed the header text to promote his newest book ''[[How To]]'' to be released 7 months later.
***He added an image of the book with large text next to it regarding the release and links on how to preorder it.
***There was no direct relation to the comics released at the time, except of course that he kind of launched his new book with all the risk it involves, while having a comic called launch risk up. It was though a very different and more real type of launch risk (of a human carrying space rocket) in the comic.
**The text:
***[The book is shown to the left as a black rectangle with large blue text and smaller gray text. On the book cover, in white drawings, are seen Megan with a ladder and either Black or White Hat (hard to say on black background). Both are looking up on Cueball who is floating in the air with a quadcopter beneath either leg, trying to plug in an electric light bulb in a naked lamp hanging down near him. It seems he has already removed the broken light bulb, as he has one in both hands. And now he tries to put in the new one. He could have let Megan use the ladder...]
***[The header in blue above it all:] How To.
***[Sub header in gray to the left of Cueball:] Absurd Scientific Answers to Common Real-world Problems
***[Author name in blue below the drawing:] Randall Munroe
***[Sub header to this below in gray:] Creator of xkcd
***[Sub header to this below in gray:] Author of what if? and Thing Explainer
***[Next to this book image are the following text:]
***[Large heading:] HOW TO
***[Normal size sub header:] Absurd Scientific Answers to Common Real-world Problems
***[In smaller gray font below:] Available September 3, 2019.
***[Four links in gray blue are given with the first word still in gray:] Preorder:[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
**It stayed up for more than two and a half month and was still up on [http://web.archive.org/web/20190422030324/https://xkcd.com/ 2019-04-22], when [[2139: Email Settings]] was up. Then it finally changed to a new header without going back to the standard.

====2018-11-07 - Back to standard text====
*[http://web.archive.org/web/20181107144453/https://www.xkcd.com/ 2018-11-07]
**The text returned to the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
***It stayed like this until [[2107: Launch Risk]] was up on [http://web.archive.org/web/20190205050302/https://xkcd.com/ 2019-02-05].
**It did not return to this standard for almost three years, but just short of a month before the third year without it, it returned on [[#2022-01-08 - Back to standard text|2022-01-08]].

====2018-11-06 - Election Day====
*[http://web.archive.org/web/20181106122850/https://xkcd.com/ 2018-11-06]:
**[[2068: Election Night]] (on election day the day after this comic was released).
***It added a larger comic above the two links from the previous header. Those links of the previous header text was still up the day before [http://web.archive.org/web/20181105105855/https://xkcd.com/ 2018-11-05], when [[2067: Challengers]] was still up.
**Randall changed the xkcd header once more to try to make more people vote, and in this case help others to vote.
***Once again directly related to the new comic about election night.
**The text:
***[A line of altering blue and red stars, blue first and last of two rows of nine starts around of the heading:]
***Election Day!
***[Below Black Hat and Ponytail to the left and Megan to the right of Cueball is checking their smart phones. Cueball is addressing the reader:]
***Cueball: The biggest thing you can do th help is to check in with friends and family and make sure they know when and where they're voting.
***[Below these four characters there is the following text with two arrows pointing left and right. Both are turning up to text/links on either side of the four:]
***Use these links to answer questions
***[To the left:] Where and how to vote: [https://www.vote.org/ Vote-org]
***[To the right:] What's on your ballot: [https://www.ballotready.org/ BallotReady.org]
***[Below was the two links from the previous header:]
***Find out where to vote: [https://www.vote.org/ vote.org].
***See what's on your ballot: [https://www.ballotready.org/ BallotReady.org]
**It was only up one day and thus on ended the day after [http://web.archive.org/web/20181107144453/https://www.xkcd.com/ 2018-11-07] when the next comic [[2069: Wishlist]] came out.
***The text then returned to the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
****It stayed like this until [[2107: Launch Risk]] was up on [http://web.archive.org/web/20190205050302/https://xkcd.com/ 2019-02-05].

====2018-11-02 - Where to vote====
*[http://web.archive.org/web/20181103021059/https://xkcd.com/ 2018-11-02]:
**[[2067: Challengers]] (on the Friday, it was released).
***It added another link to the previous header text. That text was still up the day before on Thursday [http://web.archive.org/web/20181102015102/https://xkcd.com/ 2018-11-01].
***That was while comic [[2066: Ballot Selfies]] was still up.
**Randall changed the xkcd header to let people know who is on their voting ballot, and as before there is also a link on how to register for voting.
***This is also directly related to the new comic that came out that day, about helping people to decide who to vote for, i.e. who is on their ballot.
**The text:
***Find out where to vote: [https://www.vote.org/ vote.org].
***See what's on your ballot: [https://www.ballotready.org/ BallotReady.org]
**This was done at this moment because the {{w|United States midterm election}} was held on {{w|United States elections, 2018|Tuesday, November 6, 2018}}, four days after the release of this comic.
**It was still up the day before the election day, [http://web.archive.org/web/20181105105855/https://xkcd.com/ 2018-11-05], and then it changed with the next comic.

====2018-10-22 - Register for voting====
*[http://web.archive.org/web/20181022120935/https://xkcd.com/ 2018-10-22]:
**[[2061: Tectonics Game]] (on a Monday, the 3rd day after release of this Friday comic)
***The standard text was still up Sunday [http://web.archive.org/web/20181021141446/https://xkcd.com/ 2018-10-21].
***The comic [[2062: Barnard's Star]] was released later that day.
**Randall changed the xkcd header to try to get people to register for voting.
**The text:
***Check your registration and find your polling place at [https://www.vote.org/ vote.org].
**This was done at this moment because the {{w|United States midterm election}} was held on {{w|United States elections, 2018|Tuesday, November 6, 2018}}, about two weeks after the release of this comic.
***It is generally believed that many of those not voting would have chosen democrats on election day, and thus Randall has an interest in getting as many as possible to register, see [[1756: I'm With Her]] (apart from the fact that he also most likely thinks that it is important to use the right to vote).
**It ended on [http://web.archive.org/web/20181103021059/https://xkcd.com/ 2018-11-02], when [[2067: Challengers]] came out.
***It was still there while [[2066: Ballot Selfies]] was still up the day before on [http://web.archive.org/web/20181102015102/https://xkcd.com/ 2018-11-01].

====2018-09-13 - NY votes today====
*[http://web.archive.org/web/20180913133544/https://xkcd.com/ 2018-09-13]
**[[2045: Social Media Announcement]] (the day after the release of the comic.)
***It was not up when the comic was released on [http://web.archive.org/web/20180912131437/https://xkcd.com/ 2018-09-12].
**It was a short lived reminder that NY votes today below the usual standard text.
**The text:
***xkcd updates every Monday, Wednesday, and Friday.
***NY votes today! Find your polling place [https://voterlookup.elections.ny.gov/ here]. (Zephyr Teachout for AG!)
**It ended with [[2046: Trum-]], the very next comic, on [http://web.archive.org/web/20180914175605/https://xkcd.com/ 2018-09-14], returning to the standard text.

====2017-11-26 - Christmas gifts====
*[http://web.archive.org/web/20171126130857/http://xkcd.com/ 2017-11-26]
**[[1920: Emoji Sports]] had been up two days [http://web.archive.org/web/20171125125648/https://xkcd.com/ 2017-11-25] before the message changed from the normal version. But it changed the day before the next comic came up.
***It was changed to a commercial for Christmas shopping with a code for getting 5$ of the price with a codes for different online shops.
**The text:
***To anyone looking for Christmas gifts: Until Monday you can get $5 off
***[https://www.amazon.com/What-International-Scientific-Hypothetical-Questions/dp/0544456866 What If?] and [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Thing Explainer] on Amazon with coupon code GIFTBOOK17.
***At Barnes & Noble, until Sunday you can get 20% off [https://www.barnesandnoble.com/w/what-if-serious-scientific-answers-to-absurd-hypothetical-questions-randall-munroe/1118864093 What If?] and [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432 Thing Explainer] using code GIVETHANKS.
**It was only up a few days and ended with [[1922: Interferometry]] on [http://web.archive.org/web/20171130150053/http://xkcd.com/ 2017-11-30] where it returned to the standard text.
***But it was still up when the comic in between [[1921: The Moon and the Great Wall]] was up on [http://web.archive.org/web/20171129140033/http://xkcd.com/ 2017-11-29].

====2017-09-22 - Visiting the UK====
*[http://web.archive.org/web/20170922232616/https://xkcd.com/ 2017-09-22]:
**[[1893: Thread]] (with its release).
***It was not up on the previous comic [[1892: USB Cables]], on the day they changed [http://web.archive.org/web/20170922025204/https://xkcd.com/ 2017-09-22].
**It was an announcement that Randall would visit the UK next week.
**The text:
***I'll be visiting the UK next week! You can join me in London from September 30-October 2 (at [https://live.newscientist.com/speakers/randall-munroe New Scientist Live], [http://www.rigb.org/whats-on/events-2017/october/public-lunchtime-talk--randall-munroe The Royal Institution], and [http://www.intelligencesquared.com/events/randall-munroe-on-making-complicated-stuff-simple/ Intelligence Squared]), then from October 3-6 in [https://www.stpetersyork.org.uk/public_lectures/randall_munroe_thing_explainer York], [https://www.eventbrite.co.uk/e/thing-explaining-with-randall-munroe-tickets-37832289396 Edinburgh], [https://www.toppingbooks.co.uk/events/ely/randall-murray-thing-explainer/ Cambridge and Ely], [https://www.eventbrite.co.uk/e/randall-munroe-book-signing-thing-explainer-tickets-38041072873 Oxford], and [http://www.cheltenhamfestivals.com/literature/whats-on/2017/randall-munroe/ Cheltenham].
**Ended with [[1900: Jet Lag]] on [http://web.archive.org/web/20171010045802/https://xkcd.com/ 2017-10-10] when the text returned to normal.
***But it was still up the day before with [[1899: Ears]] on [http://web.archive.org/web/20171009040109/https://xkcd.com/ 2017-10-09].

====2017-07-31 - Thank you====
*[http://web.archive.org/web/20170731021227/https://www.xkcd.com/ 2017-07-31]:
**[[1869: Positive and Negative Reviews]] (3rd day after release of this Friday comic)
***The comic [[1870: Emoji Movie Reviews]] was released later that day.
***Megan is holding hand with Cueball and next to them is two words above each other: Thank you.
***The image is also a link.
****The link goes to [http://web.archive.org/web/20170801042453/https://www.nytimes.com/interactive/2017/07/25/us/politics/senate-votes-repeal-obamacare.html How Each Senator Voted on Obamacare Repeal Proposals], an article showing the senate votes. (here in an archived version).
**Ended with [[1872: Backup Batteries]] on [http://web.archive.org/web/20170804152509/https://xkcd.com/ 2017-08-04], but was still up when [[1871: Bun Alert]] was up on [http://web.archive.org/web/20170803124342/https://xkcd.com/ 2017-08-03].

====2017-07-25 - Vote against health care bill====
*[http://web.archive.org/web/20170725103104/https://xkcd.com/ 2017-07-25]:
**[[1867: Physics Confession]] (2nd day after release of the comic, it was not up on the first day: [http://web.archive.org/web/20170724095252/https://xkcd.com/ 2017-07-24]).
**Randall modified the xkcd header to ask readers to support voting against Donald Trump's new health care bill.
***The header was replaced with an image which is available in an archived version [https://web.archive.org/web/20170726150959im_/https://imgs.xkcd.com/notes/call-senate.png here].
***The image is also a link (and you can click anywhere on it to go the the link that is mentioned).
****The link goes to [http://web.archive.org/web/20170729003307/https://www.trumpcareten.org/daily TrumpCare Ten] (here in an archived version).
****Randall has previously made it clear, in [[1572: xkcd Survey]], that he knows how to make an image a link, but not how to put the link only where he says to click.
***Transcript of the image:
****[Megan is holding hand with Cueball next to three lines of large text, the same height as they are:]
****Please tell your senators to vote against this health care bill. It will hurt people.
****[After these three lines there is a phone number in a very large bold font with a line of text below:]
****202-224-3121
****Or click here for more info
****[Below the above is a gray line which is split in the middle with gray text, and below that four state names in white text inside black boxes:]
****Know anyone in these states? Ask them to call, too.
****Alaska Maine Nevada Ohio West Virginia
**Ended while [[1869: Positive and Negative Reviews]] was up on [http://web.archive.org/web/20170731164828/https://xkcd.com/ 2017-07-31], when it was replaced by a ''Thank you''.
***That comic came out already [http://web.archive.org/web/20170728124230/https://xkcd.com/ three days before] (Friday comic), but was still up on [http://web.archive.org/web/20170730141019/https://www.xkcd.com/ 2017-07-30]) when the message changed sometimes between Sunday 30th and Monday 31st (where [[1870: Emoji Movie Reviews]] was released).

====2017-01-21 - Update on previous====
*[http://web.archive.org/web/20170122003124/https://xkcd.com/ 2017-01-21]:
**[[1788: Barge]]
**It came up almost a month after Christmas but did not really change the sales pitch of the previous. It just removed the link image with the large red text, see previous version below.
**The text:
***There are [https://store.xkcd.com/collections/featured four new shirts] in [https://store.xkcd.com/ the xkcd store],
***along with [https://store.xkcd.com/collections/posters posters] and [https://store.xkcd.com/collections/everything lots of other stuff]!
**Ended with [[1867: Physics Confession]] on [http://web.archive.org/web/20170725103104/https://xkcd.com/ 2017-07-25].
***That comic came up [http://web.archive.org/web/20170724095252/https://xkcd.com/ the day before] the above version of the header appeared.
***So the first day after release it was still the T-shirt commercial.
***And it did not return to the standard version in between.

====2016-11-28 - Christmas sale====
*[http://web.archive.org/web/20161128153015/http://xkcd.com 2016-11-28]
**[[1765: Baby Post]]
**This came up in time for the Christmas sale of 2016.
**The text was
***There are [https://store.xkcd.com/collections/featured four new shirts] in [https://store.xkcd.com/ the xkcd store],
***along with [https://store.xkcd.com/collections/posters posters] and [https://store.xkcd.com/collections/everything lots of other stuff]!
***Above the text there was an image with two black t-shirts with white print on the chest. They were located at either end of a large red text written in the text type used in the comic. This text said New xkcd shirts.
***The entire image was a link to the [https://store.xkcd.com/ xkcd store].
**Ended with [[1788: Barge]] [http://web.archive.org/web/20170121114423/https://xkcd.com/ 2017-01-21]

====Changes not documented yet 2====
*Before the above was
**xkcd updates every Monday, Wednesday, and Friday.
**Which Ended with [[1764: XKCDE]] on [http://web.archive.org/web/20161128093459/http://xkcd.com/ 2016-11-28].
*More changes could be here between this and the one below.
**Definitely some thing explainer changes here below.
*[https://web.archive.org/web/20151022200022/http://xkcd.com/ 2015-10-22] changed the header below.

====2015-09-23 - Book trip and tool====
*[https://web.archive.org/web/20150923044724/http://xkcd.com/ 2015-09-23]:
**[[1580: Travel Ghost]] was up when the header changed.
***Announcing the book trip for the [[Thing Explainer]] book as well as linking to a Thing Explainer word checker tool! Two lines of text with links.
**The text:
***News: Announcing my Thing Explainer [https://blog.xkcd.com/2015/09/22/im-going-on-a-book-trip/ book trip]. Come say hi!
***Other news: Announcing the Thing Explainer [https://blog.xkcd.com/2015/09/22/a-thing-explainer-word-checker/ word checker] tool!
****Both links are to the [[Blag]], the first a schedule for his book trip, and the second telling about Randall's new [https://xkcd.com/simplewriter/ Simple Writer] that could help you ''Write Like Up Goer Five and Thing Explainer''.
**Was there until [[1593: Play-By-Play]] was up on [https://web.archive.org/web/20151021164208/http://xkcd.com/ 2015-10-21].

====2015-09-06 - New links====
*[https://web.archive.org/web/20150906181550/http://xkcd.com/ 2015-09-06]:
**[[1573: Cyberintelligence]] was still up when the header changed.
***The promotion of the book, [[Thing Explainer]], stayed the same with a picture above links to preorder it, but the links was reduced from four to two, the amazon link changed and a new company was added for the second link removing the other three.
***See [[#2015-05-15 - Thing Explainer details|2015-05-15]] below for all details on the image.
**The new link text:
***Preorder: [https://www.amazon.co.uk/Thing-Explainer-Randall-Munroe/dp/1473620910 Amazon.co.uk}, [https://www.waterstones.com/book/thing-explainer/9781473620919 Waterstones]
**Was there until [[1579: Tech Loops]] was up on [https://web.archive.org/web/20150919220105/http://xkcd.com/ 2015-09-22].

====2015-08-09 - Back to previous header====
*[https://web.archive.org/web/20150809230825/http://xkcd.com/ 2015-08-09]:
**[[1561: Water Phase Diagram]] was still up when the header changed.
***It changed back to the exact same heading as before the one with other news here below.
****See [[#2015-05-15 - Thing Explainer details|2015-05-15]] below for all details.
**Stayed like this until [[1573: Cyberintelligence]] was out on [https://web.archive.org/web/20150905154014/https://xkcd.com/ 2015-09-05], but the only change was that the links to preorder changed from four to only two.

====2015-06-06 - Other news====
*[https://web.archive.org/web/20150606084120/http://www.xkcd.com/ 2015-06-06]
**Changed while [[1534: Beer]] was still up.
***This was just adding some "Other news", but leaving the promotion of [[Thing Explainer]] unchanged as in the [[#2015-05-15 - Thing Explainer details|previous header]], but adding two news stories in text below the link to preorder.
**The new text:
***In other news, [https://www.youtube.com/watch?v=ygrdAvmr-MA Space Weird Thing] is delightful, and I feel surprisingly invested in [https://web.archive.org/web/20150720074919/https://twitter.com/xkcdbracket @xkcdbracket's] results.
****The link to Space Weird Thing is a YouTube video with a simple words version of {{w|David Bowie|David Bowie's}} [https://www.youtube.com/watch?v=iYYRH4apXDo Space Oddity] music video, using only the top then hundred words. The creators contributes the idea to the [[1133: Up Goer Five]] diagram which also inspired the book Thing Explainer, also promoted in this header text.
****The other link is referring to [[1529: Bracket]] released 12 days before this update, as a twitter user made a survey going through all the brackets all the way to a winner was found. Seems Randall became interested in who won. See more on the comics page.
**Was there until [[1561: Water Phase Diagram]] was up on [https://web.archive.org/web/20150807181044/http://xkcd.com/ 2015-08-07]. Then it returned back to the previous header with only the promotion of the book.

====2015-05-15 - Thing Explainer details====
*[http://web.archive.org/web/20150515060322/http://www.xkcd.com/ 2015-05-15]
**[[1525: Emojic 8 Ball]]
**This was a more detailed promotion for Randall's new book: [[Thing Explainer]] to be published in November 2015, more than half a year after the announcement, compared to the previous change which was just a line and a link.
**The text:
***A picture of the open book is shown with diagrams of a human cell on the left page and suspension bridges on the right. All held in blue nuances. And arrow goes from the first word of the text to the right to the book on the left. The text is also blue except the title of the book which is in red:
****New book: Thing Explainer
****Up Goer Five-style diagrams of things (explained in the then hundred most common words)
***Below this image is a line of text with the first word in black and the other are four links to where to preorder the book:
****Preorder: [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Amazon], [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432?ean=9780544668256#/ Barnes & Noble], [https://www.indiebound.org/book/9780544668256 Indie Bound], [https://www.hudsonbooksellers.com/thingexplainer Hudson]
***The image above the preorder line is a link to the [[Blag]] post [https://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ New book: Thing Explainer].
**Changed while [[1534: Beerl]] was up on [https://web.archive.org/web/20150605082643/http://xkcd.com/ 2015-06-05], but only to add other information. The main promotion of the book stayed the same.

====2015-05-14 - New book Thing Explainer====
*[https://web.archive.org/web/20150514053623/http://www.xkcd.com/ 2015-05-14]
**[[1524: Dimensions]] was up.
***A single line announced the new [[Thing Explainer]] book, with link to the [[Blag]] post from the day before.
**The text:
***New book: [https://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ Thing Explainer!]
*The promotion of the book stayed up with some changes for the rest of the year...
**The first came already the day after so this short announcement was only up on this day and ended with the next comic. See above.
**See more details on the promotion of the book on the Thing Explainer page [[Thing_Explainer#Promotion_at_the_xkcd_home_page|here]].

====2015-02-11 - Back to standard text====
*[https://web.archive.org/web/20150211154103/http://xkcd.com/ 2015-02-11]
**The text returned to the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
***It stayed like this until [[1523: Microdrones]] was up on [https://web.archive.org/web/20150512184622/http://xkcd.com/ 2019-05-12].

====2015-02-04 - Valentine cards only====
*[https://web.archive.org/web/20150204051152/http://xkcd.com/ 2015-02-04]
**[[1482: NowPlaying]] came out as it changed.
***After the last day of ordering t-shirt had passed it changed back to the picture with the Valentine cards from the previous header, but without the t-shirt picture.
***See that [[#2015-01-29 - Valentine cards and shirt|header change]], but only the first picture described.
**Ended while [[1484: Apollo Speeches]] was up on [https://web.archive.org/web/20150210005540/http://xkcd.com/ 2015-02-10].
*On [https://web.archive.org/web/20150211154103/http://xkcd.com/ 2015-02-11] the text then returned to the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
**It stayed like this until [[1523: Microdrones]] was up on [https://web.archive.org/web/20150512184622/http://xkcd.com/ 2019-05-12].

====2015-02-02 - Last day shirt====
*[https://web.archive.org/web/20150202092804/http://xkcd.com/ 2015-02-02]
**[[1481: API]] came out as it changed.
***Just letting people know it is the last chance to order the binary t-shirt.
***There was just a line of text:
**The text was:
***Today is the last day to order the limited-run [https://web.archive.org/web/20150202092804/http://teespring.com/xkcdbinaryheart binary heart shirt]!
***The last words is link to the shirt in the shop.
**Ended before the next comic was up, but still the day after, when it was too late to order: [https://web.archive.org/web/20150203022036/http://xkcd.com/ 2015-02-03].

====2015-01-29 - Valentine cards and shirt====
*[http://web.archive.org/web/20150129183442/http://xkcd.com/ 2015-01-29]
**[[1479: Troubleshooting]] was up when it changed.
***It was to tell about both the two previous updates in the same header- Both about the collaboration to make science themed Valentine's Day cards and his new Valentine t-shirt.
***There where two pictures, with a promotion of the two products and a link to them in the shop.
***On the left was text about the cards with a small drawing to the right of the text showing the four cards.
****An ant talking to an aphids; Earth rotating about the sun but locked so one side melts; an ant with a fungus growing from it's head with a heart, and a Velociraptor skeleton where the last bit of the tail is put on by a person. The text on the cards are unreadable, but they can be seen via the link.
***The text (in three lines) was:
****Webcomic science Valentine card collaboration
****The [https://web.archive.org/web/20150127161237/http://store.xkcd.com/products/webcomic-science-valentines link to the cards] from the picture.
***The picture on the left shows binary numbers 0 and 1 in white on a black background. The middle of the three lines of those have message in red text.
***The text:
****0 1 0 1 0 Binary heart 1 1 1
****1 1 1 Valentine shirt 0 1
****0 0 0 1 [limited run] 0 0 1
****The [http://web.archive.org/web/20150125080756/http://teespring.com/xkcdbinaryheart link to the shirt] from the picture.
**Ended while [[1480: Super Bowl]] was up on [https://web.archive.org/web/20150201015913/http://xkcd.com/ 2015-02-01].

====2015-01-27 - Valentine's Day cards====
*[http://web.archive.org/web/20150127161237/http://xkcd.com/ 2015-01-27]
**[[1478: P-Values]] was up when it changed.
***It was to tell that about a collaboration to make science themed Valentine's Day cards.
***There was just two lines of text:
**The text was:
***I've teamed up with three other webcomic artists
***to make [https://web.archive.org/web/20150127161237/http://store.xkcd.com/products/webcomic-science-valentines a set of science-themed Valentine's Day cards]!
**There was a link to the cards on the store.
**Ended while [[1479: Troubleshooting]] was up [https://web.archive.org/web/20150128172147/http://xkcd.com/ 2015-01-28].

====2015-01-24 - Get shirts in store====
*[http://web.archive.org/web/20150124110707/http://xkcd.com/ 2015-01-24]
**[[1477: Star Wars]] came out as it changed.
***It was to tell about a new type of t-shirt for Valentine Day.
***There was just two lines of text:
**The text was:
***For Valentine's Day, you can get a binary heart shirt
***(from {{xkcd|99|comic #99!}}) in [http://web.archive.org/web/20150125080756/http://teespring.com/xkcdbinaryheart a limited run on TeeSpring]
**There was a link to [[99: Binary Heart]] and to the relevant t-shirt on the [https://teespring.com/ Teespring] home page.
**Ended while [[1478: P-Values]] was up [http://web.archive.org/web/20150126133139/http://xkcd.com/ 2015-01-26].

====2014-12-22 - Get shirts in store====
*[http://web.archive.org/web/20141222233233/http://xkcd.com/ 2014-12-22]
**[[1463: Altitude]] came out as it changed.
***After the Christmas sale deadline there was still merchandise in the [https://store.xkcd.com/ xkcd store].
***There was just a line of text:
**The text was:
***You can get xkcd shirts, prints, and posters in the [http://shop.xkcd.com/ store]!
**The word store was a link to the shop.
**Ended while [[1476: Ceres]] was up [http://web.archive.org/web/20150123102318/http://xkcd.com/ 2015-01-23].

====2014-12-19 - Back to previous header====
*[http://web.archive.org/web/20141219092349/http://www.xkcd.com/ 2014-12-19]:
**[[1462: Blind Trials]] came out as it changed.
*It changed back to the exact same heading as before the one with order now here below.
**See [[#2014-12-17 - Christmas deadline|2014-12-17]] below for all details.
**Ended while [[1462: Blind Trials]] was still up [http://web.archive.org/web/20141221172450/http://www.xkcd.com/ 2014-12-21].

====2014-12-18 - Order now====
*[http://web.archive.org/web/20141218090650/http://www.xkcd.com/ 2014-12-18]
**[[1461: Payloads]] was still up when it changed.
***It was to alert that the deadline for shipping before Christmas from the [https://store.xkcd.com/ xkcd store] was Friday and that it was rapidly approaching. This was a follow up on the [[#2014-12-17 - Christmas deadline|Wednesdays announcement]] the day before.
***The image was just four lines of text with several red and blue words.
**The text was:
***The xkcd store Christmas shipping deadline is Friday!
***Once it passes, there is no going back. The arrow of time drags us all
***Inexorably forward toward decay and disorder. toward the end of all things.
***Towards the empty silence of the grave. Order now!
**The entire drawing was a link to the [https://store.xkcd.com/ xkcd store], not just the blue text.
**Ended a day later while [[1461: Payloads]] was still up [http://web.archive.org/web/20141216084107/http://xkcd.com/ 2014-12-16].

====2014-12-17 - Christmas deadline====
*[http://web.archive.org/web/20141217085320/http://www.xkcd.com/ 2014-12-17]
**[[1461: Payloads]] came out as it changed.
***It was to alert that the deadline for shipping before Christmas from the [https://store.xkcd.com/ xkcd store] was Friday. This was announced Wednesday two days before the deadline.
***The image was just text with the last word in each line in red and the xkcd store blue as a link.
**The text was:
***Looking for a gift?
***xkcd store Christmas shipping deadline is Friday!
**The entire drawing was a link to the [https://store.xkcd.com/ xkcd store], not just the blue text
**Ended a day later while [[1461: Payloads]] was still up!

====2014-12-03 - Christmas shopping====
*[http://web.archive.org/web/20141203132024/http://www.xkcd.com/ 2014-12-03]
**[[1455: Trolley Problem]] came out as it changed.
***It was to announce the start of the Christmas shopping on the [https://store.xkcd.com/ xkcd store]
***Four boxes with shipping details are shown. Two green and two red, alternating from green. Between them are three text messages in two, two and three lines.
**The text was:
***xkcd store
***Christmas shopping
***I will probably not ship you a bobcat.
**The entire drawing was a link to the [https://store.xkcd.com/ xkcd store].
**The bobcat is a reference to [[325: A-Minus-Minus]].
**Ended while [[1460: SMFW]] was up [http://web.archive.org/web/20141216084107/http://xkcd.com/ 2014-12-16].

====2014-11-29 - Thanks - Emily====
*[http://web.archive.org/web/20141129211604/http://xkcd.com/ 2014-11-29]
**[[1453: fMRI]] was still up when it changed.
***It was to thanks for all the help his friend Emily with cancer got through among other his previous header text [[#2014-11-27 - Help Emily| Help Emily]].
***That only needed to be up two days before the goal was met.
**The text was:
***Thank you for helping my friend Emily.
***It means so much.
**Ended three days later while [[1454: Done]] was up [http://web.archive.org/web/20141202065133/http://xkcd.com/ 2014-12-02].

====2014-11-27 - Help Emily====
*[http://web.archive.org/web/20141127005239/http://xkcd.com/ 2014-11-27]
**[[1452: Jurassic World]] came out as it changed.
***It was to help a friend who got cancer by raising money for her.
**The text was:
***Hey all. My friend Emily—the economist who helped
***me with my {{xkcd|980|money chart}}—has been fighting cancer. She's
***having a rough time and could use some [http://web.archive.org/web/20141128183414/http://www.gofundme.com/e07dqk help]. Thank you.
**There are two links, one to the [[980: Money]] comic she helped Randall create, and one for her Go Fund Me page to raise money for her cancer cure.
***The help link above is to the archived version from that time, but the link was still active in August 2019: [https://www.gofundme.com/e07dqk Helping Emily Fight Cancer].
**Ended while [[1453: fMRI]] was up [http://web.archive.org/web/20141128070838/http://www.xkcd.com/ 2014-11-28].
***She did thus not get a permanent header as did Becky on the [[#Seven_Years|Seven Years]] comic.

====2014-10-02 - what if? bestseller====
*[http://web.archive.org/web/20141002211139/http://xkcd.com/ 2014-10-02]
**[[1428: Move Fast and Break Things]] was up when it changed from the [[#2014-09-02 - what if? book out|book is out]].
**This was a month after the [[what if|what if?]] book came out.
***It added a line of red text beneath the previous header to announce that the book was the #1 New York bestseller.
**The text was:
***My book is out!
***(#1 New York bestseller!)
**The entire image was a link to the [https://whatif.xkcd.com/book/ The Book] page on the [https://whatif.xkcd.com/ what if?] page on xkcd. post.
**Ended while [[1451: Background Screens]] was up [http://web.archive.org/web/20141125234520/http://xkcd.com/ 2014-11-25].

====2014-09-04 - what if? book out====
*[http://web.archive.org/web/20140904150600/http://xkcd.com/ 2014-09-04]
**[[1416: Pixels]] was up when it changed from the [[#2014-09-02 - what if? book out today|book is out today]].
**This was two days after the [[what if|what if?]] book came out.
***It only removed to today from the previous header, that had only been up two days.
**The text was:
***My book is out!
**The entire image was a link to the [https://whatif.xkcd.com/book/ The Book] page on the [https://whatif.xkcd.com/ what if?] page on xkcd. post.
**Ended while [[1428: Move Fast and Break Things]] was up [http://web.archive.org/web/20141001130827/http://xkcd.com/ 2014-09-01].

====2014-09-02 - what if? book out today====
*[http://web.archive.org/web/20140902125802/http://xkcd.com/ 2014-09-02]
**[[1415: Ballooning]] was up when it changed from the [[#2014-07-23 - what if? book tour|book tour header]].
**This was the day the [[what if|what if?]] book came out. [[Cueball]] standing to the left of the text with arms raised shouts this out.. The word Book is underlined and blue to indicate a link.
**The text was:
***My book is out today!
**The entire image was a link to the [https://whatif.xkcd.com/book/ The Book] page on the [https://whatif.xkcd.com/ what if?] page on xkcd. post.
**Ended while [[1416: Pixels]] was still [http://web.archive.org/web/20140903134518/http://xkcd.com/ 2014-09-03].

====2014-07-23 - what if? book tour====
*[http://web.archive.org/web/20140723180600/http://xkcd.com/ 2014-07-23]
**[[1398: Snake Facts]]
**This was a promotion of his book tour for the [[what if|what if?]] book made by [[Cueball]] standing to the left of the text with arms raised. Several parts of the text was underlined and blue to indicate links.
**The text was:
***I'm going on a book tour! click here for a list of stops.
***Or click anywhere-this whole image is one link because I've never gotten the hang of HTML imagemaps.
**The entire image was a link to the [[Blag]] post: [https://blog.xkcd.com/2014/07/22/what-if-book-tour/ What If book tour!].
***Later Randall commented on this lacking ability in the comic: [[1572: xkcd Survey]].
**Ended while [[1415: Ballooning]] was still up [http://web.archive.org/web/20140901113916/http://xkcd.com/ 2014-09-01].

====2014-03-13 - what if? announced====
*[http://web.archive.org/web/20140313070951/http://xkcd.com/ 2014-03-13]
**[[1341: Types of Editors]] was up.
**This was the first promotion of Randall's new [[what if|what if?]] book which is shown next to two lines of text.
**The text was:
***News:
***I'm publishing a ''what if'' book!
**The entire image was a link to the [[Blag]] post: [https://blog.xkcd.com/2014/03/12/what-if-i-wrote-a-book/ What if I wrote a book?]
**Ended while [[1397: Luke]] was up [http://web.archive.org/web/20140722142115/http://xkcd.com/ 2014-07-22].

====Changes not documented yet 1====
*Before the above was up till [http://web.archive.org/web/20140312041127/http://xkcd.com/ 2014-03-12]:
**xkcd updates every Monday, Wednesday, and Friday.
*More changes could be earlier than this.

[[Category:Design of xkcd]]

779: Anxiety

2021-10-22T07:49:20Z

141.101.105.35: /* Explanation */

{{comic
| number = 779
| date = August 13, 2010
| title = Anxiety
| image = anxiety.png
| titletext = Don't need any, thanks. I have a backscattering fetish.
}}

==Explanation==
Some people are upset about airport security policies that mandate the use of {{w|backscatter X-ray}} machines, since the machines can create an image of the subject naked. [[Black Hat]] is selling {{w|Sildenafil|Viagra}} for men since many men feel self conscious (or anxious, as the name puts it) about their size when flaccid,{{citation needed}} who might wish to "put their best foot forward" and look their best, as it were. Seeing as this is Black Hat, this may also be a means to thumb their noses (so to speak) at the system by forcing the security guard to see them with erections. The problem with this approach is that, presumably, the time spent in a line of this length will be far too short for the Viagra to have any effect whatsoever. However, judging by the security guard's thought bubble, he is already looking at an image of a guy with a large erection, who is the current subject of the scanner.

In the title text, one of the people in the line explains he has a {{w|sexual fetish|fetish}} with being X-ray scanned, and thus doesn't need Viagra to achieve the above effect.

==Transcript==
:[There is an airport security checkpoint where a queue of ten passengers is waiting to go through a backscatter x-ray scanner. Near the back of the line, Black Hat is standing next to a stand and a sign which says "Viagra $20". One passenger next to him is drinking a glass of water, probably just before taking the pills; another is contemplating the sign.]
:Security Guard (thinking): Oh god.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Ponytail]]
[[Category:Physics]]
[[Category:Sex]]
[[Category:Multiple Cueballs]]

Talk:2531: Dark Arts

2021-10-21T12:40:14Z

141.101.105.35: Comment

Whoo, my first "first explanation". It's not a particularly thorny comic but my explanation could still use some judicious editing I'm sure. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 06:51, 21 October 2021 (UTC)

I added a "citation needed" to the claim that letting arbitrary websites modify your filesystem is a Bad Idea, because I couldn't resist >.<
[[Special:Contributions/172.68.132.74|172.68.132.74]] 08:40, 21 October 2021 (UTC)
:{{citation needed}} [[Special:Contributions/162.158.88.113|162.158.88.113]] 10:45, 21 October 2021 (UTC)

The previous comment is almost worth an XKCD comic of its own. --[[Special:Contributions/162.158.203.24|162.158.203.24]] 10:10, 21 October 2021 (UTC)

WTH did Randal do that lead him to put ext4 and javascript in the same search, and why does he think hardlinks are the problem with such a cursed search? [[Special:Contributions/172.69.69.182|172.69.69.182]] 10:17, 21 October 2021 (UTC)

Which specific IT professional is the explanation referring to? [[Special:Contributions/141.101.105.35|141.101.105.35]] 12:40, 21 October 2021 (UTC)