This is not such a great idea, but it probably can be tweaked. First, it needs some automated targeting. Does anyone know how AdSense targets ads? I bet the ad

This is not such a great idea, but it probably can be tweaked. First, it needs some automated targeting. Does anyone know how AdSense targets ads? I bet the ad ends up on the pages that would be returned from a Google query containing the keywords. The better pagerank, the more expensive the ad. I do not have in mind a good algorithm for adpinion, but they should figure something out - Google's targeting is really good.. Second, upclicking doesn't matter and the button is not even needed. The only way the user indicates he likes the ad should be to click through. Third, do not just count votes. Implement the best open recommendation algorithm from Netflix prize contest instead. Downclicking that hides the ad is good and useful.