Like Lurker

Someone who only likes comments on a wall post, rather than the actual wall post itself, and contributes nothing to the conversation.

Gee John, it was good you were liking my comments on that facebook argument I was having, but I wish you had backed me up too! You're such a Like Lurker.

like lurker

To be on Facebook and only "like" things. Never comment, never post, never add anything new to the conversation.

John always "likes" things, but never says anything. He is such a like lurker.