Like, I said, if people want to get together and buy the domain from Bill, I'll cover the hosting and the ongoing annual registration renewal fees. (And set up the Wiki-type system and such, of course, if that is what you want to do.)
Heck, I'll even throw $50 into the pot to help buy it from Bill too.
Basically, I feel like whoever ends up donating to get to the $500 gets a "vote" or whatever of what to do with it as time goes on. I think most of us, for now, think that a History Wiki makes sense. If we decide to do something else two years down the road, so be it.