When someone does something on Facebook just to make a point, or have everyone else see it. Can be done by a status, or joining of a group. Usually not a direct comment or wallpost.
Facebook news feed: Brain just became a fan of "Harvard Business School Class of 2014"
Carlos: Man, Brain is such an asshole, he just wants everyone to see that and rub it in their face. He's just conspicuous facebooking like always.
Status: Meg just got a 2400 on her SAT!
Julie: Meg is such a jerk, everyone knows she's a fucking genius, why does she have to gloat all the time?
When someone new as joined facebook, and he/she does not have many friends, wallposts or photos. In most cases, this is a relatively short period of time, before the 'facebookling' grows out of control into a Self-Mutating-Facebook-Monstrosity.