Mark Zuckerburg gives a keynote in 2008. Photo by Brian Solis (CC).

On Feb. 4, 2004, Harvard University student Mark Zuckerburg launched Facebook, the most popular social networking service in the world.

Facebook was founded by Zuckerburg and his roommates Chris Hughes, Eduardo Saverin, Andrew McCollum and Dustin Moskovitz.

According to Business Insider, it started out as Facemash, a game that pulled student photos from Harvard’s website and allowed them to compare their peers by attractiveness. After coming under scrutiny for it, the site was relaunched as the Facebook, a social network. The “the” was removed in 2005.

Facebook was originally limited to Harvard students but soon extended to other colleges in the area and then to most universities and corporations in Canada and the U.S. By late 2006, anyone over the age of 13 with an email address could use Facebook.