4. Mozilla Foundation
First Address: 466 Ellis St., Mountain View, CAIn an ordinary office cubicle, intern Blake Ross and programmer David Hyatt were working on a new browser for Netscape's Mozilla project after Netscape Navigator was crushed by Microsoft's Internet Explorer. The browser was called Firefox, and it became the first to give Explorer real competition since Navigator's market share collapsed. Both men left Netscape before it was disbanded in 2003, but the Mozilla project lives on.