Someone posted this earlier in a thread, and I thought it was fantastic from a cognitive meets algorithm standpoint. There are lots of hidden gems. And thanks to whoever posted the link!

Add an aspect for meeting people + free iPod to the top player at the end of each month, and you've got a successful startup, no?

This image recognition game has been out there for a while. There have been other efforts. And yet image search still sucks. Why?

He makes a comment in the Q&A about using a restricted photo set. And the other answer, I think, is that he's an academic rather than representing business interests.

I don't see why someone doesn't clone the game but pulling flickr and picasa photos. With the scale he's talking about with gameplay, that knowledge of the photos would be very valuable to one of those two existing search engines and could come together very quickly, like, say, a few months.