Facebook is a popular free social networking website. It was founded in February 2004. It allows registered users to create profile, upload photos and video,send messages and keeps us in touch with friends,family and colleagues. The site is available in 37 different language include public features. It helps us to get friend and to know many people.The websites membership initially limited by the founders to Harvard university students. it gradually added support for students at various other universities students be opening high school students and eventually to any one aged 13 and over. Facebook now allows any users who declare themselves to be at leas 13 years old. User must register before using the site. After that they may create a personal profile,add other users as friend and exchange message. Users may join common interest user groups ,school,college,workplace etc. In September 2012 Facebook has over one billion active users.