Facebook
Facebook is a social networking service used to exchange messages. you can also create common-interest user groups, and pages for events and organizations.
Mark zuckerberg had the idea for facebook in 2003 while he was studying at Harvard university. The original name was facemash. At the same time, three other students, camerom and tyler winklevoss and divya narendra, were working on a similar site called harvardconnection.com. zuckerberg was working on his idea, when Cameron and tyler asked him to help them with their website. For a while,zurkerberg worked on both projects. The winklevosses believed that while zuckerberg was working for them,he used some of the harvardconnection ideas to build his own site.
In 2004,zuckerberg launched thefacebook and within the first month, more than half of the undergraduate students at Harvard were using the site. The name later changed to facebook and became hugely popular.
In 2012, facebook had over 900 million active users and the average facebook user had over 200 friends.