(noun) The individual, or group of individuals, involved in obsessive adoration of a particular facebook friend where a close relationship does not exist in real life. The Facebook Groupie will like or comment on almost any status update, even when they don't undertsand the meaning or are not involved in the conversation, and live under the illusion of a close relationship. Often, there is a symbiotic relationship with the facebook whore. The FBG is distinguishable from the stalker because their comments are not discouraged.
Tiffany: I'm not really sure why Chuck commented on that--he has no idea what we were even talking about.
Jim: Meh--he's just one of those Facebook Groupies (FBG).