Google actually played around with a voting feature awhile back. When you searched for a term, there was an up arrow on the results, so it moved those results to the top every time you searched for those terms. This was incredible useful for me, because for example I was too lazy to bookmark api documentation and just search for example rails api, and the links I voted up were automatically at the top. If this works like this I will be happy, the social aspect I don't care for, but can see how it will be relevant if enough people are voting for good content.. thats associated with specific search terms.