If it has not occurred to you, Facebook is an incredible resource for hackers stealing ID’s. People put in all sorts of personal information that can be used by hackers. I would never put my real birth date or any other information asked for by financial institutions on Facebook.
It is bad enough that individuals and private teams attack people. But, now governments and terrorist organizations are attacking private individuals. It is not just the Pentagon in DC or the CIA at Langley that are targets. You too may be a target, especially if you work for the Defense Department.
Since the Human Resources section of the US government was hacked, Office of Personnel Management (OPM), which holds details on the entire staff of US government (reference), foreign governments know who works where.
Facebook has announced they will be providing new warnings when they detect likely government hacking attempts. See: Notifications for targeted attacks.