Or do what Treyarch have done with WaW and Bungie has with H2 and 3 in that all games you've played are saved to your stats.
... or even just save the demo so others can see it too. I remember even 10 years ago sharing Counter-Strike demo's with friends. Why it's not used in every multiplayer game I have no clue. Being able to watch other peoples skills is great for training and competitions.
Another use is to prove someone else is cheating. I lost count of the demos of CS I had to watch as a server admin. We even had cheats such as wallhacks to prove the player was following the enemy through the wall.
