For some reason I finally started poking around in Amazon's Mechanical Turk last week. It figures Andy'd be way ahead of me and used mturk for his latest project Girl Turk.
Andy also links to this survey done (on mturk of course) asking why the turkers turk. I read all of the responses (the whole time visualizing myself getting paid for each of those tasks) and there seems to be a general theme running: people do it because they want to kill time and they like seeing the money accumulate. I wish the surveyor would have asked how much people make on a weekly basis.
Seeing Andy's experiment go so well, performing a few HITS mysefl, and reading these responses, I'm suddenly completely fascinated with the system.