- created in 2004 by Mark Zuckerberg and friends
- named after a book that was given to students so they would get to know each other
- at first limited to just Harvard
- in 2005, High School Facebook
- 2006, opened to everyone (older than 13)
- by 2012, over 1 billion active users
- 2nd most visited site after Google
- sensing Twitter growth, June 2013, Facebook introduces clickable #hashtags