Well you counted Facebook as a big success in terms of advertising, but they aren't exactly raking in cash. To me that puts it similar to Hulu and Demand--making significant revenue, but the real money comes from an IPO.

For the most part we're not talking public companies, so it's hard to be completely accurate. But I think it's safe to say that there are a lot of online advertising funded businesses who are providing strong returns to their partners/investors.