That depends on how you define the beginning of the company. For example, Zuckerberg had built quite a few different "social" websites before building Thefacebo

That depends on how you define the beginning of the company. For example, Zuckerberg had built quite a few different "social" websites before building Thefacebook. Jobs and Woz had been building circuit boards and other electronic devices for a couple years before they built the Apple I.