While I wasn't here for the implementation of karma, I suspect it was a practical joke by the admins, directed at users who were asking for a reputation system on the board. I would class MR's karma as a satire of reputation systems on other forums. It is, however, aptly named: the precise workings of karma are one of Buddhism's four "imponderables."
Off topic (
), I've noticed here and elsewhere that many, many people misspell "palindrome" in a very specific way: dropping the
n. It's less often used, but proportionately as common as substituting "weary" for "wary." What's up with that?