If you are keeping money until the project is done, couldn't you just make money by investing the money for the time you are keeping it? Also, the people giving you money are already paying that price, because they can't invest the money elsewhere.
True, and that's definitely one of our ideas. But mynameishere's right -- it's very hard to make ends meet with just interest on funds held. Unless you happen to get really popular really fast. But in that case you'll probably need more staff or resources, and then you're back to square one.
As far as people paying that price, our thoughts are that we're a "collaborative funding" service, not just a bank, so people will be okay with paying a small cut for the service. (Except for open source: there our philosophy is "you're helping the world, so we'll help you".) We'll find out soon enough if they aren't, I guess. :-)
Paypal originally tried to draw all revenues off the float (IIRC), and it didn't work too well. Of course, it didn't hurt with respect to attracting customers.
The economists' answer is doubtless, "what the market will bear", which is of course of no practical use. Thanks to the web, you could do some trial and error - some users get different prices, or you can run promotions, stuff like that, so you can see how people respond.
It might not be ideal for what you guys are doing, but think about a site with many users buying many different things. It's easy to sneak some changes in there to see how people respond to differential pricing.
From your squeezedbooks summary: "Many web sites, especially airlines, and even amazon.com, change prices for each individual on the site based on their behavoir." Huh, I didn't know that. The plot thickens ... I'm going to be really careful with my mouse movements next time I book a flight. :-)
Yes, it's really annoying to be shopping for an airline ticket, make a significant amount of requests (10-20) with different parameters (dates, airports, etc) only to see your first quote rise when enter it again :-/.
