Mark Zuckerberg, 23, founded Facebook while studying psychology at Harvard University. A computer programmer interested, Mr. Zuckerberg had already developed a number of social networking websites for fellow students, including Coursematch, which allowed users to see people taking their degree, and Facemash, where you could assess the attractive people.
In February 2004 Mr. Zuckerberg launched "The facebook" as he was known at first; the name taken from the paper sheets distributed to freshmen, profiles of students and staff. Within 24 hours, 1,200 Harvard students had signed up, and after a month, more than half the undergraduate population had a profile.
The network quickly spread to other universities in Boston, the Ivy League, and finally, all US universities. He became Facebook.com in August 2005 after the address was purchased for $ 200,000. Secondary schools in America could register from September 2005, then began to spread throughout the world, reaching universities in the UK next month.
In September 2006, the network was extended beyond educational institutions to anyone with an email address registered. The site remains free to join, and make a profit through advertising revenue. Yahoo and Google are among the companies that have expressed interest in a buyout, with figures rumored around $ 2 billion (£ 975m) is discussed. So far Mr. Zuckerberg has refused to sell.
The characteristics of the site have continued to develop during 2007. Users can now give gifts to friends, post free classified ads and even develop their own applications - graffiti and Scrabble are particularly popular.
This month, the company announced that the number of registered users has reached 1.3 billion, which is the site of larger social networks with an educational focus.
Earlier this year there were rumors that Prince William had been registered, but later revealed to be a mere impostor. Congressman David Miliband, Jo Whiley radio DJ, actor Orlando Bloom, artist Tracey Emin and the founder of Wikipedia, Jimmy Wales, are among the confirmed high profile members.
This month, officials banned a water fight flash mob style in Hyde Park, organized through Facebook, due to public safety fears. And there was more controversy in Oxford as students realized that the university authorities were reviewing their Facebook profiles.
The legal case against Facebook goes back to September 2004 when Divya Narendra, Cameron and Tyler Winklevoss brothers, who founded the social networking site ConnectU, accused Zuckerberg of copying their ideas and coding. Zuckerberg had worked as a computer programmer for them when they were all at Harvard before Facebook was created.
The case was dismissed on a technicality in March 2007 but without a fault.