xp lobby

I've seen people posting out XP Lobbies... What is that all about? I'm thinking that players just stand around and let one another shoot eachother? Am I on the right track? That seems pretty lame to me, but maybe that's why I have been playing all the time and am still only level 16? What are...

Ok guys my name is travis.. I have black ops for wii , can anyone please give me there fc (friend code) if they do black ops only xp lobbies!!! My fc is : 4267-5354-3790 please send me a ally request if u do xp lobbyss!