Mark Zuckerberg, along with his college roommates, launched 'Thefacebook', initially limited to Harvard students.
Peter Thiel made the first major outside investment of $500,000 in Facebook, helping the company grow.
Facebook opened registration to anyone over 13 with a valid email address, beyond just college students.
Legal battles ensued between Zuckerberg, Saverin, and the Winklevoss twins over the ownership and founding rights of Facebook.