I really like the idea but it needs to be clear.
What about the other side of the coin? Do the investors become a part of the company?
As an investor, I would like to own even a fraction of the company.
What's there to ensure the startups wouldn't just be irresponsible with the money invested?
What if you don't have enough social capital?
I think you should try to show answers to these questions on your start up page or a how it works page or a video. Not explicitly but implicit thru examples of your service being used. I know that you have raised money for your demo, but how much? who gave? what did you give in return? what steps did you take to ensure you will be responsible?
Most of the returns seem to be undying gratitude / a thank you note in a small community project, not equity.
If you have social capital why not put a paypal link on your facebook / twitter?
I mean, my knowledge of both this startup and kickstarter is pretty thin, and there is certainly nothing wrong with competing with something similar.