Every post you 'like'. Every friend you add or fan page you join. Every place you check in, and every Web page you recommend.
In fact, to us these actions are a way how we enjoy and use this social network. But to Facebook, it is a way how they get those billions.
In business, it is said that if you're not paying for something, you are not a customer. Then who are we? We are the… product.
In this case, you're a product worth, to Facebook, an average $4.84 a year.