In practice, how much user-created content is distributed now through XBL?
Next to nothing. And by that I mean that you *could* count Red Vs. Blue episodes (Halo machinima) as user-created.
Lord knows the entire 80-160 MS point system for gamer pics and themes would be completed invalidated with user-created content. "I have to pay to get a set theme that other users can have too? Don't see that enforced on PC."
The first pack was free. The second pack has a timed-fee, so it will be free in September (*cough* just in time for Halo 3!).And were the Gears of War maps free or did they charge? That might be an indication of how much publishers have a say in whether they charge or if they charge, what the pricing would be (look at record companies clashing with Apple over iTunes pricing).
Anyways, I don't see why no one else has copied Ubisoft Montreal's solution with FarCry Instincts/Predator. They created a fairly robust map-making tool on the Xbox and maps could be shared between users. What a controversy that became, eh? Oh wait... :|