Stamped

We'll be the first to admit that the idea of signing up for yet another social network sounds about as fun as a dinner date with a dead man, but Stamped (Free) might just be cool enough to make it worthwhile. The idea is that you put your stamp of approval on, well, just about anything — books, restaurants, music, games, movies, and more — and share your stamps with your friends, who likewise share their stamps with you. The nice part about the whole thing is that there are no 1-5 star reviews or anything like that. You simply stamp something you totally love (so they're all basically 5-star recommendations), and you're initially limited to 100 stamps. So you can't go on a crazy stamping spree, recommending every single one of your Usher remixes.