A person who comments on a status update or anything else similar to that and ruins a good conversation between two people.
Mark: "So i was totally
flirting and gaming up Alicia over on her status update."
Carlos: "Oh rlly? What happened?"
Mark: "It was all going good i was totally
making an impression and about 25 comments in this douche posted a comment and just ruined it. She stopped replying after that."
Carlos: "Wow what a Chat Blocker!"