
Facebook is a global social networking
website that is operated and privately owned by
Facebook, Inc. Users can add friends and send
them messages, and update their personal profiles to
notify friends about themselves. Additionally, users
can join networks organized by city, workplace,
school, and region. The website's name stems from the
colloquial name of books given at the start of the
academic year by university administrations with the
intention of helping students get to know each other
better.

Mark Zuckerberg founded Facebook with his college
roommates and fellow computer science students Eduardo
Saverin, Dustin Moskovitz and Chris Hughes while he
was a student at Harvard University. The website's
membership was initially limited to Harvard students,
but was expanded to other colleges in the Boston area,
the Ivy League, and Stanford University. It later
expanded further to include any university student,
then high school students, and, finally, to anyone
aged 13 and over. The website currently has more than
250 million active users worldwide.

A January 2009 Compete.com study has ranked
Facebook as the most used social network by worldwide
monthly active users, followed by MySpace.