20. Ben Silbermann and Evan Sharp

Cofounders, Pinterest

Pinterest, an online scrap-booking site that lets users organize photo pins onto different boards, is now worth $11 billion after raising a $367 million round of funding in March, followed by another $186 million in May. Investors include Andreessen Horowitz, Fidelity Investments, and Bessemer Venture Partners.

The site continues to grow and adapt its business model, most recently releasing new options for advertisers. Instead of just choosing to pay for views or clicks on promoted pins, advertisers can choose to pay with a cost-per-engagement model or cost-per-action model. Pinterest just lost its head of partnerships however, Joanne Bradford. The rumor is Pinterest wasn't generating as much revenue as it should have.