It's somewhat unfortunate that technology is moving a lot faster than the law can keep up with. Among some groups of people, Facebook is essentially the modern-day version of the phone network: how they do their routine communication. But the phone network has a bunch of legal protections, e.g. if the police want to listen in on some conversations they need a warrant, <i>even if</i> the phone company were willing to sell them a wiretap without a warrant (that's why the warrantless-wiretapping scandal was a scandal). But Facebook is currently just treated as a simple case of a company that has some information, which the government can purchase if it wishes.