> you have to be conscious of the fact that the conditional probability of everything working just right at the same time is orders of magnitude smaller than something like gittip being executed with better understood tools and structures.

Sure, that's why I'm encouraged that Gittip has grown as well as it has! We paid out $41,000 our first year. We paid out $300,000 our second year. The best justification I can offer will be a strong year three. ;-)