Startup to fund Startups

While poking around HN we always see stories about startup's being funded, how to bootstrap your startup, startup's seeking funding etc... From my perspective it's strage that in order to fund a startup or to be considered an investor to a startup you have to have an elite status already.

How about a startup to fund startups by allowing the general public to buy shares of the startup, sure there are lots of 'issues' to think about here but it's possible right ?

Maybe I'm late to the party and something like this already exists and I'm not aware... anyone ?