This is a new program that Facebook is trying out where you get Facebook Credits in exchange for watching some ads. It's an expansion of an earlier deal they made with a company called Trial Play. So you're playing a game and you get an offer to earn more Credits by watching a short video advertisement. I can't think of very many other scenarios where you get paid to watch advertising. And you're not technically being paid here either, at least not in cash. But you are being paid in the currency that Facebook relies on and manages, and it's the currency that all Facebook apps will be required to run on by this summer. The emergence of Credits and the permutations of it by Facebook are the real story here because in addition to making its own internet, Facebook is making its own economy.