Facebook is an American for-profit corporation and an online social media and social networking service based in Menlo Park, California. The Facebook website was launched on February 4, 2004, by Mark Zuckerberg, along with fellow Harvard College students and roommates, Eduardo Saverin, Andrew McCollum, Dustin Moskovitz, and Chris Hughes.
The founders had initially limited the website's membership to Harvard students; however, later they expanded it to higher education institutions in the Boston area, the Ivy League schools, and Stanford University. Facebook gradually added support for students at various other universities, and eventually to high school students as well. Since 2006, anyone who claims to be at least 13 years old has been allowed to become a registered user of Facebook, though variations exist in the minimum age requirement, depending on applicable local laws. The Facebook name comes from the face book directories often given to United States university students.
Facebook, Inc. held its initial public offering (IPO) in February 2012, and began selling stock to the public three months later, reaching an original peak market capitalization of $104 billion. On July 13, 2015, Facebook became the fastest company in the Standard & Poor's 500 Index to reach a market cap of $250 billion. Facebook has more than 2 billion monthly active users as of June 2017. As of April 2016, Facebook was the most popular social networking site in the US and the world, based on the number of active user accounts. Facebook classifies users from the ages of 13 to 18 as minors and therefore sets their profiles to share content with friends only.