In the meantime, I've been thinking about user generated content, and in particular quests. User generated quests are one of those ideas that people love to throw around*, but that's hard to actually implement for the very simple reason that users suck at making quests. There are plenty of exceptions, of course, and I'm sure that many people who have been game masters for tabletop RPGs could manage it, but most players don't have a very clear sense of balance (especially where there own characters might be involved), and there's a big difference between the mindset that focuses on "this sounds cool" and the one that focuses on "this would produce a good user experience."
But user generated quests are a cool idea, so how would you add them to a game (I'll assume we're talking about an MMORPG, here). The way to get good user-generated quests is to actually give them as little control as possible over the method of completing the quest. A user generated quest could work like this:
2) At least some of the components are hard for him to personally acquire (perhaps one is found on a magic-resistant monster)
3) Wiz132 creates a quest: Bring me the eye of the Magic-Resistant Jabberwocky. He decides what the player needs to do (bring him the eye), and what the reward is.
4) The meat of the quest, that is, the part where another player will have to explore a dungeon/hunt a creature through the woods/sneak into the creature’s lair and fight it is determined by the game world and the existing game mechanics, not by Wiz132.
Now if someone goes and does this quest and brings the quest item to Wiz132, they’ll receive the reward. This should happen whether or not Wiz132 happens to be online (an NPC version will appear in his laboratory if he is not). Another issue here is: how does the player get to decide what rewards to give? Money seems straight-forward, but do they also have to give up xp to finance the quest reward? That might be interesting, but I’d be more likely to include some kind of item the player can acquire that can be used to create quests worth a certain amount of experience.
Now you might wonder how this is different from a player running around killing everything in sight and then selling the rare drops they get in an auction house? Well, aside from the fact that they can get experience, as well as money, you could solidify this quest concept by requiring the user to have the quest in order to make progress on it. For instance, what if the monster in question doesn’t even appear unless someone with the quest shows up to fight it? Or perhaps the monster exists, the but the eye only drops for people with the quest.
The point is that user generated content should both feel like part of the game, rather than a separate activity the player can do instead of playing, and it should be fairly high-level. User generated content, as part of a game, shouldn't be asking the player to take on the role of game developer, but give them a way to add to the content of the world simply by playing it.
*I hear that City of Heroes is going to get a quest creation tool sometime soon. I'll be interested to see what that looks like.