Rob Goldman, Vice President of Ads, at Facebook, wrote that Facebook product is social media and the ads exist to fund that. For the question: “If I’m not paying for Facebook, am I the product?” – Rob Goldman replied: “No.”
Facebook clarified that is not selling data to advertisers. Facebook says that much like TV, Radio or Newspapers, Facebook is selling advertisers space on Facebook.
Facebook uses the data to show better and more relevant ads, to show reports to advertisers about the campaign performance. Facebook don´t share information that personally identifies a user.