Investing in startups online

I've seen plenty of websites that utilize philanthropic crowd-funding, but I'm unable to find any websites that allow people to purchase equity online. Are there any? If not, for what reason?

Note: I'm talking about private startups that have almost no capital, so don't say E-trade.

For a very good reason that in the US, the JOBS act was only passed last year and SEC are behind the eight-ball in issuing guidelines (supposed to be Jan this year). However, professional investors (those the tax-dept deems rich enough not to feel ripped off) have always had access to private placement or angel syndication platforms.

It's not the lack of demand (for capital by startups) that is the problem but separating the genuine companies from scams. If too many pops&mums get ripped off, the SEC is just going to cop the blame (again) and people being burnt are not going to trust any crowd-investing site. So it behooves genuine investors and cash-hungry startups to wait for the guy with big stick.