Mark Zuckerberg founded Facebook in 2004 while attending Harvard University. Facebook began as a student directory but expanded to allow users to connect and share online. Zuckerberg dropped out of Harvard after his sophomore year to focus on Facebook full-time. Under Zuckerberg's leadership, Facebook has grown to over 2 billion users worldwide and made Zuckerberg one of the richest entrepreneurs with a current net worth over $17 billion. Though successful, Zuckerberg remains focused on his vision of connecting the world and improving Facebook.