Facecocking
The unnecessary use of social media when a private message is more appropriate - usually with the intent of indirectly showing off.
An example of Facecocking as written on someone's facebook wall:

"Hey girlfriend - I'm in a cab in New York right now. Meet me outside the club in five minutes."

"Hey dude can I borrow your bike? I'm going to ride across the country tomorrow. It's going to be rad."