Facebook is a social networking site that allows users to create profiles, connect with friends and share photos, videos, and interests. It started in 2004 for college students and is now widely used. Key features include profiles, photos, groups, events, and applications. Though originally for students, half of users are now outside of college. It has over 50 million active users and growing rapidly. Students are heavily represented but others are joining. Facebook can be addictive due to its constant updates and ability to stay connected with others. Some downsides include overuse and privacy/stalking issues.