[Daigotsu]

It's hard to say. Having it just user run you forfeit nearly half of the things that a lot of people participate for (like items for avatars, actual cannon plot, contest for site currency/tokens). You'd almost have to have site backing to get the most bang for buck. Then again, this is only my opinion.

To advertise, I'd say you ring up some of the more active, popular users/artists to sponsor said user event. Have them put it in their signatures, or to talk about it. Kind of like Celebrities supporting things. Not that we specifically have "Trisphee Celebs" here, but you know. More widely known users would have more substantial pull with that kind of thing.