Flickr has this cool new thing - Park or Bird which will identify if your photo is in a national park and/or if it contains a bird.  It looks pretty neat and the sample photos provided all work perfectly (as you'd expect for sample photos provided).

Curious about the ability of the algorithm to work with a different photo I searched through my photo archive to find one with a bird in it and tried it.  Uh, oh - park or bird failed to recognize the presence of a bird in the photo.  I guess they still have some work to do with their algorithms.