Facebook

Facebook, Inc.

Type	Private
Founded	Cambridge, Massachusetts (2004)
Founder	Mark Zuckerberg Eduardo Saverin Dustin Moskovitz Chris Hughes
Headquarters	Palo Alto, California, U.S., will be moved to Menlo Park, California, U.S. since June 2011
Area served	Worldwide
Key people	Mark Zuckerberg (CEO) Chris Cox (VP of Product) Sheryl Sandberg (COO) Donald E. Graham (Chairman)
Revenue	US$800 million (2009 est.)
Net income	N/A
Employees	2000+(2011)
Website	facebook.com
IPv6 support	Yes, special URL www.v6.facebook.com
Alexa rank	2 (February 2011[update])
Type of site	Social network service
Advertising	Banner ads, referral marketing, Casual games
Registration	Required
Users	600 million (active in January 2011)
Available in	Multilingual
Launched	February 4, 2004
Current status	Active
Screenshot of Facebook's homepage

Facebook (stylized facebook) is a social network service and website launched in February 2004 that is operated and privately owned by Facebook, Inc. As of January 2011^[update], Facebook has more than 600 million active users. Users may create a personal profile, add other users as friends and exchange messages, including automatic notifications when they update their profile. Additionally, users may join common interest user groups, organized by workplace, school, or college, or other characteristics. The name of the service stems from the colloquial name for the book given to students at the start of the academic year by university administrations in the US with the intention of helping students to get to know each other better. Facebook allows anyone who declares themselves to be at least 13 years old to become a registered user of the website.
Facebook was founded by Mark Zuckerberg with his college roommates and fellow computer science students Eduardo Saverin, Dustin Moskovitz and Chris Hughes. The website's membership was initially limited by the founders to Harvard students, but was expanded to other colleges in the Boston area, the Ivy League, and Stanford University. It gradually added support for students at various other universities before opening to high school students, and, finally, to anyone aged 13 and over.
A January 2009 Compete.com study ranked Facebook as the most used social network service by worldwide monthly active users, followed by MySpace. Entertainment Weekly put it on its end-of-the-decade "best-of" list, saying, "How on earth did we stalk our exes, remember our co-workers' birthdays, bug our friends, and play a rousing game of Scrabulous before Facebook?" Quantcast estimates Facebook has 135.1 million monthly unique U.S. visitors in October 2010. According to Social Media Today as of April 2010, it is estimated that 41.6% of the U.S. population has a Facebook account.