Is it possible that if you log into Facebook from your phone, they have a way in to the phone to grab data? Is that what this means?
I suppose that is possible, but I doubt what it means, All your Facebook activity is logged, where you were when you viewed and interacted, and what you typed - who you are interacting with. This creates as much of a "map" as taking your phone SMS to and from data, and everybody else's, and building a map of your associates -- and doing the same thing for everybody else.
The government can get all of this data from Facebook, no warrant needed. Contrast with getting pen and trace data from phone company, where pen and trace laws come into play.
18 U.S. Code Chapter 206 - PEN REGISTERS AND TRAP AND TRACE DEVICES