This document provides an overview of Facebook's history and business model. It discusses how Facebook was founded in 2004 by Mark Zuckerberg and initially focused on connecting college students. It then expanded rapidly across college networks and saw major growth over the following years. The document also summarizes Facebook's revenue sources, which became primarily from advertising, challenges it faced around user privacy, and how it introduced new features like photo sharing and the news feed. Competitors like Twitter and key platforms that drove engagement like games and the developer platform are also mentioned.