Naval Ravikant, AngelList

Naval Ravikant and Babak Nivi
Entrepreneurs Ravikant (shown here) and Nivi created AngelList in February 2010 to help open up the clubby world of startup financing. The site has become a sort of LinkedIn for entrepreneurs and investors looking to connect. To date, more than 500 startups have successfully used AngelList to land funding from some of its 3,000 member-investors.

In 2011, AngelList quintupled its volume. It's also enabling new startup hubs around the country. A map of startups and investors connected through AngelList lights up not just Silicon Valley and New York, but Florida, Oregon and Arizona. Plenty of big VC shops--Kleiner Perkins Caulfield & Byers and Andreessen Horowitz among them--now use AngelList to hunt for deals.