Unless you're literally mindlessly staring at known data, you're learning. Social status updates and such are essentially a game, and they teach various aspects of social politics.
Dubious what useful skills most people can actually get from that but you can definitely "get good at facebook", as you put it. (And before anybody jumps on me - I hate facebook and I despise the completely fake life that comes out of the gaming aspects of facebook, but I can appreciate its values as a game designer)