Facebook Zombie
A Facebook user who hides when they're not using Facebook so they don't get unfriended. It's like they're a ghost. They come out only to post something stupid and then vanish again.
'I'm gone. Don't unfriend me.'
'I'm back. I'm still not unfriending you. #notunfriendingyou'
'I deactivated my account because I'm too lazy to be unfriended.'