Category:No title text

It's rare for an xkcd comic to lack a title text. Among those, most are extra comics or are part of the A Smarter Planet series. Only three of the numbered comics have lacked title text, likely due to these comics being a new kind of interactive comic where title text isn't included as an option. The comic 404: Not Found doesn't have a title text because it's a 404 error page. There are also some comics that have more than one title text.

I do occasionally fix typos and things but to my knowledge none of the comics were ever missing a tooltip. It's all in a database (overbuilt, I know) and I think I would have noticed an empty field. More likely someone was just confused by their browser's erratic tooltip display behavior. Sometimes you have to do little incantations (or mouse over a link and then back onto the picture) to get them to appear.

—Randall Munroe, Source