Facebrity = Facebook Celebrity
Someone who is immensely popular in the facebook circles, and whose photos on facebook are visited a number of times by his/her friends, their friends, and by their friends' friends!
Guy1: Did you check out Megan's latest photos?
Guy2: Yeah, man those are awesome, just like her other 459 photos!
Guy1: Yeah, I guess she is a celebrity of sorts.
Guy2: Yeah, a celebrity on facebook; Facebrity!!