This is different than Theater Mode but they kind of go together. You can upload full games to your file share for others to view. Also you can upload custom game types as well.
At this point in time there are 6 spots total for your file share. Those of use with a capture card, no big deal because we can record what we want and delete.
Those without one, should look into our prestige membership because we will record your videos for you. But if you still don't want to do this the Call of Duty Theater is in BETA right now that allows you to link your YouTube account with your Call of Duty account.
We have yet to get confirmed data on how long or large a video can be for uploading to your YouTube. You shouldn't have to worry about how quickly you get to the recent game because Treyarch is saving a "fuck load". You'll see 100's of recent games and Treyarch will be deleting as they see fit but should not be an issue like on Halo where you had to do your recent 5 games or so. Play all night long and still go back and find your 2nd or 3rd game.
The Theater and File Share is still kind of shaky and there are some hiccups but Treyarch is working on it and we should have much more info soon.