I'm not sure why you're referring to it as a "joke." Humans.txt is definitely an earnest effort to standardize a means of giving the people behind building and maintaining a website credit for their work.
HumansTXT is not just a joke though. It's like movie credits for programmers.
Google was quick to add it, though I'd hoped they would have enhanced it a bit by now. At least it hasn't washed away.
http://humanstxt.org/
The joke is itself a play on the "robots.txt" protocol that sites use to indicate whether they may be crawled by search engines.