Randall added a Bitcoin address to two pages of his site and changed it many times over the years, as a high-tech equivalent of a tip-jar. Here's a quick list of all the addresses mentioned in this article that have appeared in the footnote on xkcd.com and on xkcd.com/bitcoin, along with the earliest web archive available:
1Lg2rvxbBPC8jp2YJoV5xL7sdyTjueMUot, April 14th, 2011
14FHqYSgAi39CEJksUJJsK8JzJzyqFpLVk, January 15th, 2012
1NEPgrUmed3VyXpqbYZom7YVJ8MozYrNWx, April 28th, 2013
14Tr4HaKkKuC1Lmpr2YMAuYVZRWqAdRTcr, May 5th, 2013
1NfBXWqseXc9rCBc3Cbbu6HjxYssFUgkH6, June 4th, 2013
1FhCLQK2ZXtCUQDtG98p6fVH7S6mxAsEey, June 27th, 2014
The first address was added to xkcd.com/bitcoin, which today returns a 404 error. The first web archive of the page is dated April 14th, 2011, and its contents have been changed four times. On the #xkcd-bitcoin channel on irc.foonetic.net, he explained why he created it:
We don't have donations of any kind, actually. I mean, there are prints you can buy, and you can pay more if you want. I only learned about bitcoins a month or so ago. I don't solicit donations on my website, and I have avoided soliciting donations through various systems where I hadn't decided to actively promote those systems (i.e. flattr and bitcoin). [...]
Here's how far I'll go: if anyone types this URL, they can see a black hole into which they can deposit bitcoins: http://xkcd.com/bitcoin/. it'll be interesting to see if anyone stumbles on it. I am probably legally obligated to let you know that I am not a charity and will probably be spending the money on extremely unwise things (i.e. gin).Hooray! I have some bitcoins now.
The original address was
1Lg2rvxbBPC8jp2YJoV5xL7sdyTjueMUot, but between April 14th, 2011 and June 1st, 2011, Randall replaced it with a message explaining why he decided to remove it:
Thank you for all the kind donations! I took down my address because I would prefer to experiment with Bitcoin as a regular, anonymous user. I put up an address here because someone on IRC asked, but I don't want an xkcd.com donation address to be seen as an endorsement of Bitcoin to xkcd readers.
As a bitcoin user, I stand to profit from encouraging waves of new adopters who drive up bitcoin prices. I'm uneasy about this conflict of interest; for the moment, I'd rather stay a normal user. Again, thank you to everyone who sent me bitcoins before I took this down! I'll try to use them for something fun and geeky.<3 Randall
The message was then removed before August 12th, 2011 and the page remained empty until a new address was added between August 12th, 2011 and January 15th, 2012:
14FHqYSgAi39CEJksUJJsK8JzJzyqFpLVk. It was then replaced by the last address to be shown on the page,
14Tr4HaKkKuC1Lmpr2YMAuYVZRWqAdRTcr, between March 16th, 2013 and May 5th, 2013. It remained there until the page was shut down after November 24th, 2017.
Between February 18th, 2013 and February 24, 2013, Randall edited the footnote on xkcd.com and added a Bitcoin addresses. Over time, he changed them four times (before eventually removing it), but they were always displayed in this format:
- BTC 14FHqYSgAi39CEJksUJJsK8JzJzyqFpLVk
The first address to be added to the footnote was
14FHqYSgAi39CEJksUJJsK8JzJzyqFpLVk, which was also the second address to appear on xkcd.com/bitcoin. It was added between February 18th, 2013 and February 24th, 2013, months after it was initially introduced on the Bitcoin page.
The three addresses that followed were both never present on the Bitcoin page and only appeared on xkcd.com. First, it was replaced by
1NEPgrUmed3VyXpqbYZom7YVJ8MozYrNWx between April 23rd, 2013 and April 28th, 2013, which was then changed into
1NfBXWqseXc9rCBc3Cbbu6HjxYssFUgkH6 between June 1st, 2013 and June 4th, 2013. Finally, either on June 26th, 2014 or June 27th, 2014, it would be changed for the last time into
The footnote containing the Bitcoin address would be removed entirely, along with the xkcd warning above it, on September 12th, 2016, when 1732: Earth Temperature Timeline was the frontpage comic. They were probably removed to not scare potential new fans away, given the popularity of the comic.