The forums weren’t really a great place to post news, so davean helped me set up a blag here. I’ve got a bunch of news/info on a bunch of topics, and will answer questions in the comments, so here we go...
The Blag is the official xkcd blog. Its name is an intentional typo of the word "blog", inspired by the comic 148: Mispronouncing. It was launched in October 2006, 6 weeks after the publication of that comic. It is unlikely Randall had associated his neologism with the widespread UK version of the term (typically equivalent to using fast-talking 'patter' to close some minor but significant 'off-book' deal) as this was neither integral nor humorously averted in his own usage.
Since 2012, updates to the blog have been sporadic, and most new posts are now about Munroe's books or book tours. There were no posts to the blog between November 24, 2015 and February 5, 2019, most likely due to the three-year gap between the promotional cycles of Thing Explainer and How To. As of November 2019, the most recent post unrelated to Munroe's books was ISEE-3, published on May 30, 2014. The blog seems to be abandoned, with the last blog post being on September 25, 2019.