Today, in “ridiculous specification I've come across in the course of entirely legitimate work” …
In case just typing a status message wasn't good enough, XEP-0108: User Activity defines an XMPP extension for telling your contacts precisely what you're up to in a machine-readable form … as long as it's one of a rigidly-defined taxonomy of activities. Buying groceries is a kind of chore, whereas shopping is supposedly a form of relaxation; I think some might disagree that you're inactive while praying.
RFC 4480: Rich Presence Extensions to the Presence Information Data Format goes a step further and allows you to specify that you're in a location that's too dark for video, too noisy for audio, and inappropriate for IM. Your mood can be “invincible”, but—distressingly—neither “quixotic” nor “apathetic” are permitted. I think I'll stick to LiveJournal.
(Oh, the title of this post is valid per RFC 4480. Edit: or it would be if it weren't mangled. Time to migrate.)