Facebuddy - That person who's on your friend list but has never talked t

That person who's on your friend list but has never talked to you and probably thinks you're a weirdo.

My facebuddy has 500 friends and still doesn't know who I am. I feel like a ghost.

I'm friends with my teacher on Facebook. He's my facebuddy. I'm not even allowed to talk to him outside class.

My facebuddy is my uncle. He doesn't know I'm his niece. It's like a family secret.