It's a shame there's a huge chicken vs egg problem with bootstrapping the initial receipts, because I think once you have some receipts up from a few charities people might be a whole lot more giving.
I sent a teeny-tiny donation, figuring that if a bunch of people donated an inconsequential amount of money, they could absolve themselves that in the event it turns out you were taking everyone for a ride, no one got burned any great amount. So far though, it doesn't look like that's happening yet, the number of (even tiny, inconsequential) donations is ridiculously small.
I've got a sneaking suspicion that this whole exercise is simply going to show the folly of the Libertarian "charity can do it instead of government aid" position, in that I don't think the real world really works that way.
Oh and one more thing: Red Cross is on the front page, but not in the list of charities with addresses.