Google +1 takes the concept of Likes in Facebook book or RTs and Favorites in Twitter and brings it to their search. The big question is, will it take off. I can already tweet about what I like. That enhances search data for Google. Personally I think I might get a bit freaked out if I was say searching for well dating services or porn and say my uncle's preferences showed up. But this is the way things are going and Google probably had to introduce something like this.
We are still anticipating a much bigger system called Circle coming soon. This is a fairly minor effort to make Google Search more social.