Yea, that's basically it, or at least that falls squarely into the category together with some other things. The most common by far is a sort of communal roleplaying where the actions of the protagonist are determined by the community but you do everything else.

There are a lot of sites with communities that do these things, usually the games/roleplaying section of various forums or image boards. There are also sites that specialize in them, in which case it's usually some specific type of them such as illustrated ( http://www.mspaforums.com/forumdisplay.php?85-Forum-Adventures ), branching+anonymous+collaborative ( http://www.epicsplosion.com/epicsploitation/adventures ), etc.

If you wait a week or so, the lesswrong forums will probably be a good place for you to start a tradition of them, in case you don't want to learn the culture of some existing place. You could also run it on that biog you already have and rely on the comments functionality.

I follow a lot of these things, in a lot of places, and know a fair bit about how to make one successful, so if you're ever in doubt or interest or inspiration is inexplicably dying feel free to ask me.

Oh, and please post a link here whenever you start so I can read it and suggest things.