By way of John Battelle’s SearchBlog:
Amazon Mechanical Turk provides a web services API for computers to integrate “artificial, artificial intelligence” directly into their processing by making requests of humans. Developers use the Amazon Mechanical Turk web services API to submit tasks to the Amazon Mechanical Turk web site, approve completed tasks, and incorporate the answers into their software applications. To the application, the transaction looks very much like any remote procedure call: the application sends the request, and the service returns the results. In reality, a network of humans fuels this artificial, artificial intelligence by coming to the web site, searching for and completing tasks, and receiving payment for their work.
The service is legit — http://mturk.amazon.com/ redirects to the main site.
On first blush it sounds similar to OpenMind (which was started by David Stork, a coworker of mine). OpenMind has especially been used to gather human knowledge for training up AIs (especially common-sense knowledge) — I wonder where Amazon expects to go with the idea.