Here's a look at what you need to know about social media giant Facebook.
Facts: According to Facebook's most recent annual report (from 2012), it has more than one billion monthly active users around the world. The company also estimates that it has more than 600 million daily active users. There are approximately 159 million monthly active users in the U.S.
It is blocked in North Korea and most of China.
There are more than 4,600 employees at Facebook, and it is headquartered in Menlo Park, California.
Facebook introduced words such as "friending" to the lexicon.
Timeline: February 4, 2004 - "The Facebook" is launched by Mark Zuckerberg, Dustin Moskovitz, Chris Hughes and Eduardo Saverin at Harvard University.
March 2004 - Students at Stanford, Columbia and Yale universities are allowed to join Harvard students on Facebook.
June 2004 - The company moves to Palo Alto, California.
September 2004 - The Facebook "Wall" is added.
December 2004 - One million users are active on the site.
September 3, 2005 - High school students are allowed to join Facebook.
September 20, 2005 - The company drops "the" from the name and becomes Facebook.
December 2005 - The number of Facebook users reaches six million.
May 2006 - Facebook allows people in work networks to join.
September 5, 2006 - The "News Feed" is introduced on Facebook.
September 26, 2006 - Facebook becomes open to everyone 13 or older.
July 2007 - Former Harvard classmates Cameron and Tyler Winklevoss sue Zuckerberg, alleging that he stole the idea for Facebook from them.
October 2007 - Microsoft buys a 1.6% stake in Facebook for $240 million.
January 5, 2008 - ABC News and Facebook co-sponsor a debate between presidential hopefuls.
March 2008 - Facebook hires Sheryl Sandberg to be the company's chief operating officer.
2008 - The Winklevosses settle their suit with Facebook for $65 million.
2009 - Facebook settles a lawsuit with founder Eduardo Saverin out of court.
February 9, 2009 - Facebook introduces the "Like" button.
June 2009 - Facebook becomes the number one social network in the U.S., surpassing MySpace.
October 2010 - The movie "The Social Network, " a fictionalized account of the start of Facebook, is released.