Facebook is a social networking website, launched on February 4, 2004.
Facebook was founded by Mark Zuckerberg, a former Harvard student. Initially the membership of Facebook was restricted to students of Harvard College. It was subsequently expanded to MIT, Boston University, Boston College, Northeastern University and all Ivy League schools within two months. Many individual universities were added in rapid succession over the next year. Eventually, people with a university (e.g .edu, .ac.uk, etc.) email address from institutions across the globe were eligible to join. Networks were then initiated for high schools on February 27, 2006 and some large companies. Since September 11, 2006, anyone 13 or older may join. Users can select to join one or more participating networks, such as a school, place of employment, geographic region, or social group.
The site has more than 64 million active users (including non-collegiate members) worldwide. From September 2006 to September 2007 the site's traffic ranking increased from 60th to 7th, according to Alexa. It is the most popular website for uploading photos, with 14 million uploaded daily.
The name of the site refers to the paper facebooks depicting members of the campus community that some U.S. colleges and preparatory schools give to incoming students, faculty, and staff as a way to get to know other people on campus.
Facebook has met with a certain amount of criticism and controversy in its short lifespan, mainly because of privacy concerns, but also due to the politics of it's founders and some censorship issues.