From Citizendium, the Citizens' Compendium
Facebook is a social networking website owned by Facebook, Inc and based in California. In 2004 it was founded by Mark Zuckerberg, then a student at Harvard University, and was initially only for Harvard students, before expanding to other Ivy League colleges, then institutions worldwide, until finally opening to anyone aged 13 or over.
Facebook's system allows users to join networks of people organized by region, workplace or educational institution. It also allows membership of 'groups' on virtually any topic. The site is a popular resource for political campaigning and activism as well as for keeping in touch with friends and colleagues.
