Facebook began in 2004 as a social networking platform for Harvard students. It allows users to create profiles, share photos and statuses, and connect with friends and pages. Key features include the News Feed, Messenger, search, and marketplace. Facebook now has over 1.18 billion daily active users who spend an average of 20 minutes per visit. It generates over $5.6 billion in quarterly revenue, largely from advertisement. Businesses can create pages to interact with customers and leverage Facebook's tools for marketing, customer relationships, and content sharing. Optimization best practices for brands include encouraging user participation, special discounts, boosted posts, and focusing on high quality, shareable content.