A person who has a Facebook account but rarely ever posts anything about themselves, but is constantly tagged in photos, makes comments, likes posts, has tons of wall posts from friends, thus showing they use the site on the regular basis, but simply read others posts to see what is going on in others lives only to say to you face to face "Oh yeah, I saw that on your Facebook"
Shannon: I can't stand Amy. she has a Facebook but never post anything about herself on Facebook, but when I see her she says "Oh yeah I saw that on Facebook"
Mike: Yeah she is a Facebook Sponge
Mike: Yeah she is a Facebook Sponge
by JohnnyFleekins July 27, 2010