Why Is Google Image Labeler Fun?

Google's trying to improve its search results for images. Since those folks know that computers can't really understand what is in an image, it's asking people to do it for them, taking crowdsourcing, to a new extreme. The Google Image Labeler site shows,

You'll be randomly paired with a partner who's online and using the feature. Over a 90-second period, you and your partner will be shown the same set of images and asked to provide as many labels as possible to describe each image you see. When your label matches your partner's label, you'll earn some points and move on to the next image until time runs out. After time expires, you can explore the images you've seen and the websites where those images were found. And we'll show you the points you've earned throughout the session.

Of course I tried it. It was fun for the 90 seconds. Me and Raider2044 got 2100 points - though I'm not sure why that didn't show up on the leader board. I can't imagine why anyone would want to do this for too long though, especially long enough to get 91300 points. Maybe people like seeing their 'net name published on a Google site.