I can add yet another approach to your list, the one that we've developed for trustedones.com (a trust-based social networking app). Basically, we mimic the wo

I can add yet another approach to your list, the one that we've developed for trustedones.com (a trust-based social networking app). Basically, we mimic the word-of-mouth recommendation model. The people you trust the most, are those you know well - yourself, friends, their friends, and then all trusted ones (the wisdom of the crowds). You build your own network of people you trust, and quickly slice and visualize information. Here are a few links that you may find interesting. We're still tweaking stuff, so let me know if you have any thoughts on what we can do better. http://arnox.trustedones.com http://arnox.trustedones.com (my page) http://maps.google.com/?q=http://www.trustedones.com/feeds/gearthinl/arnox.kml%3Ftopic=%26wisdom=0 http://maps.google.com/?q=http://www.trustedones.com/feeds/g... (all of my local recommendations on a map) http://www.trustedones.com/topic/restaurant-local/listing/boston-beer-works_112-canal-st-boston-ma http://www.trustedones.com/topic/restaurant-local/listing/bo... (sample recommendation)