Microsoft's released a Halo Waypoint video - after the break - detailing the point behind the upcoming Halo fan's Live home.
There's two bits to it, basically: "Intel" and "Career". Intel's just tons of stuff from the Halo universe in general, including fiction, upcoming anime, and so on. The Career bit tracks your accomplishments across multiple Halo games. ODST, Halo 3 and all DLC related to them are supported at launch.
It's out in November. Thanks, Joystiq.
Update - IGN's posted up some shots.