On the other hand, I like the idea of shares and badges being a finite commodity. Would make you really careful about what you shared, wouldn't it? Which maybe would in turn make people think very carefully about what they posted and how. Can't tell though whether that would encourage more thoughtful exchange or just de-incentivize regular use.
Yes, that's as much the point as raising money is (maybe even more so, given that we're talking about pennies both literally and figuratively). That's why I termed it "Hubski Economy" instead of just an idea to raise money. Donation schemes don't have this interesting element that could evolve in unexpected ways the way a 'living' system can. It's kinda game theory applied to the social network idea. I don't know if it's been tried before, but I don't know too much about the internet in general.