The whole point of the site is the get involved with everything Call of Duty. You'll sign up and create your profile, and from there you can complete a variety of "missions" to earn points and level up. This include posting in the forums and taking part in polls, but you'll unlock more missions the further you progress within the site.
Why does this sound like a video game? It's a website -- but a pretty good one at that. The Intel and Reconnaissance (that is, news and media) sections should be updated regularly, and a developer blog is up and running. Off you go, then!
[Via press release]
