The whole recent foofaraw about fanfiction (which apparently erupts with tiresome regularity every time a Big-Name Author opens his mouth about it and says something mildly non-fan-friendly) got me thinking about a project I had considered briefly a while back: creating a fanfiction-friendly "shared universe" project which anyone could contribute to.
The core of the idea is simple. I create a world, documented in a wiki or some other central location, which I also use as a source for my own fiction. Other people can do the same, under the caveat that the results have to be distributed in a non-commercial context. They would be free to contribute copies to the wiki I've created as well.
It sounds simple enough, but there's a part of me that thinks such things have a tendency to outrun their creators. One wrinkle is the relative lack of legal weight for things like the Creative Commons license — from what I can tell, it has never been tested in court, and essentially consists of a civil contract not to press legal action. (CC-BY-NC-SA would, I presume, be the exact license in question.)
Further complications include vagaries about what constitutes commercial use: "Whether or not a use is or is not commercial will depend on the specifics of the situation and the intentions of the user, as stated in the definition." So I'd probably have to draft my own notes about what I'd consider commercial use, and even then I'm not totally sure what applies and what doesn't. E.g.: if someone writes a one-off fanfiction for hire, is that "commercial use" in the same manner as selling multiple copies of a story for profit?
Gray areas, it seems, are par for the course.