According to Wikipedia and its Info page, Facebook was launched exactly six years ago, on February 4, 2004. Back then it was called Thefacebook, and it was originally located at thefacebook.com, but it's definitely the same project.

Facebook has celebrated its sixth anniversary with several new features and a home page redesign. The new features include a "Photos" dashboard that allows users to browse recent photos of all their friends from one page, and a "Chat with Friends" feature that shows which of a user's most popular friends are available to chat. Also, they fixed a privacy issue in the "Applications" dashboard that emerged earlier this week and caused some concern.





The changes are being rolled out to a small number of users initially, before being deployed more widely in the coming months. The changes mean that users will be able to send messages to friends in their social network directly from the Facebook homepage, rather than having to open a separate window, and there is more emphasis on search, with a larger search box appearing on the page.

Facebook has also streamlined the Live Feed and News Feed sections, which enabled users to see what their friends were doing at the moment. Both have been integrated into a single News Feed, with a "Most Recent" tab for live updates, and other highlights filed under the "Top News" tab. Some navigation buttons have also moved from the top and bottom of the homepage to a pallette on the left-hand side of the screen, and videos uploaded to the social-networking site now appear under the Photos section.

You can read more here.

Founded by Mark Zuckerberg, Eduardo Saverin, Dustin Moskovitz and Chris Hughes, Facebook was originally intended to be a network only for Harvard students, but was later expanded to other universities and finally to everyone. Intelligent design, a lot of smart business decisions and gradual expansion made Facebook what it is today: by far, the biggest social network on the Internet.