Here's yet another way to harness the wisdom of the crowd for your personal gain: TrustedOpinion, a recommendation engine that creates product ratings based on reviews that are weighted by the writers' proximity to you in your social network.
Your friends' opinions carry the most weight. The opinions of their friends (your friends-of-friends) carry less. Your friends-of-friends-of-friends still less, and so on. The thinking being that you're more likely to trust your friends' takes on product reviews than those of people you don't know. If you want, you can control the weightings even more, individually scoring people in your network as an expert (or not) in particular categories.
It may sound confusing, but TrustedOpinion does a very good job of representing the data it's processing. When you're looking at the network's review of a product, you see, in a rotating 3D view, the 1-to-10 ratings your friends gave the product as numbers in close orbit around you (you're at the middle). Their friends are a level out, and so on. TrustedOpinions calls this the Radar Score, and it does a very good job of simplifying data. The system also shows you how your own calculated rating on a product is different from the site-wide average.
The system can also display a list of products ranked on scores, which is a useful tool to see what your friends like best. And you can turn the data around, to find out which of your friends are the best match for your tastes. I could see this function being used in dating services.
Categories other than music will likely be added soon.
I like the way TrustedOpinion blends social network data with user evaluations. However, I strongly feel that TrustedOpinion is more feature than product. In other words, this functionality belongs in Netflix itself, or in Amazon, or Facebook, or maybe even in CNET. Greene says that next year the company will focus on offering the service to other companies, but he maintains that the service can work quite well as a standalone product--he says TrustedOpinion has acquired a quarter million users in a few months, with no advertising or marketing.
If you don't mind building yet another instance of your personal social network, it's worth trying out. If you do mind, wait a few months and hope that the service is indeed integrated into existing networks.