First used primarily on the member wall on Facebook. Generally one user will post on another user's wall, or will be walled, followed by the second user posting on the original poster's wall in a repeated fashion until the messages from both parties have overtaken the board.
User A's Message Board:
User B (12:30AM): Lol what? What's the matter?
User B (12:10AM): The hell are you talking about?? People are STILL talking about that. Go you! Haha..
User B (12:03AM): Yeah! Over by the bar... who was that chick you were with?
User B (12:00AM): I saw you last night!
User B's Message Board:
User A (12:40AM): That turned out NOT to be a chick... Goddamnit... Tomorrow is going to suck.
User A (12:20AM): Oh dear God...
User A (12:08AM): Oh, that was nobody... Damn, nobody saw that, right?
User A (12:02AM): No you didn't..