Year Founded: 2009
Founded By: Marc Andreessen, Ben Horowitz
Notable Investments: Skype, Zynga, Instagram

If one person could be tapped to be the face of the modern-day tech book, Marc Andreessen would be the guy. As the founder of Netscape, the first web browser, Andreessen has seen the web grow from nothing into the glue that connects the world. Along with co-founder Ben Horowitz, the firm has helped guide some of the biggest Internet companies of the past few years including Skype, Facebook, and Twitter, of which it was one of the first investors. And to think it's only been around for four years.