Picture this 6 Sep 2006

Based on Luis von Ahn's ESP Game, Google Image Labeler puts two random users together and gives them 90 seconds to suggest a label (or tag) for a random image pulled from Google's database. The idea is that if both people come up with the same label, it's probably a good one and can safely be added to the metadata used to describe the image. In this way, Google can use human brain power to optimise its image search results.

While asking users to tag content is hardly new (with many large sites, such as Flickr and Amazon, adopting this approach extensively), it is interesting to see it employed under the guise of a game. Image search is also the ideal area to employ this technology within, as it's very difficult for a computer to tell what an image is about. Imagine the challlenges involved in establishing that an image is "The Persistence of Memory", a "surrealist painting" by "Salvador Dali", for example.

But just how effective will this technology prove? Messing around with Google Image Labeler is fun for a few minutes (or as TechCrunch puts it "fun, in a why-am-I-doing-this kind of way") but surely it will take a zillion years to tag every image in the Google database, won't it? Well apparently not. Luis von Ahn thinks that this game could effectively label all Google-indexed images in just two months.

Sources: SearchEngineWatch, TechCrunch and Google Blogoscoped.