Facebook

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, 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 high school, place of employment, or geographic region.

The site has over 58 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 number one site for photos in the United States, ahead of public sites such as Flickr, with over 60 million photos uploaded weekly.

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.