Well, to the Call of Duty players in here, It seems that like Bungie's Halo, they will have a new system (Service), called: Elite.
The beta will be out on July 14. They will make the beta tests with Black OPS Multiplayer system, so we won't actually get to taste the full service, because most of the functions will release with Modern Warfare 3.


This is the site of the beta sign up:

Call of Duty: Elite