I disagree. Facebook makes their money from advertisers. The advertisers go where people are, but they are also careful about paying. For example if their pr

I disagree. Facebook makes their money from advertisers. The advertisers go where people are, but they are also careful about paying. For example if their product is only applicable to one gender, but the ads would go to everyone then they'd want to pay half as much. Sites that do not have demographic information about their users consequently can't charge anywhere near as much as Facebook which gets advertisers to pay more for the demographics they want. Even if everything in your FB profile is a lie, your friends then provide the demographic information about you. eg you are going to similar to them. And because you are on Facebook, you are now available to the advertisers.