If you're playing (or have played) any of the Battlefield franchise games, you really need to check out Stats Verse. It's everything the official Battlefield website on EA should be - a simple interface that keeps track of your progress during the game. In a way it's too easy, because once you check your stats after playing for a while the chances of becoming obsessed with your progress in the game grows exponentially.
There's a "community" (read: forum) that's decent, but it's really about the stats. They track XBOX 360, Windows and Playstation 3 play for all the Battlefield games, and will presumably also cover Battlefield 3. I also found the ability to check what the top players of the game were using (favorite weapons, classes etc.) really helpful in trying to figure out my own gameplay.
It would be great if it worked with all shooters, but for now it only works with the Battlefield games and Medal of Honor. You can check out the list of all the games at StatsVerse.com or you can get obsessed yourself at the Battlefield Bad Company 2 version here.