You are being watched. The Facebook has a secret system, a machine that spies on you
John Reese: I never understood why people put all their information on those sites. Used to make our job a lot easier at the CIA.
Harold Finch: Of course. That's why I created them.
John Reese: You're telling me you invented online social networking, Finch?
Harold Finch: The Machine needed more information. People's social graph, their associations. The government had been trying to figure it out for years. Turns out most people were happy to volunteer it. Business wound up being quite profitable, too.