Searching content of images

A few days ago I mentioned the game approach for annotating images of Louis von Ahn, that makes use of free computation cycles of humans. A straigthforward use of the side effect of playing the games milliones of times, is a search engine for images. Here you can try prototypes for two search image engines:

1. Search for images according to overall subject of image
2. Search for objects within images

Although the amount of images considered is still limited (tens of thousands), the approach seems promising.