Facebook was created by Mark Zuckerberg in 2004 when he was a student at Harvard University. It was originally intended to be a game in which photos of students were compared and rated according to who was the most attractive. The project was banned by the college within days, but it later became the basis for the social-networking site we know today. At first, membership was granted only to students, but later all people over the age of thirteen were allowed to join. Today, Facebook is actively used by over one billion people.