Facebook is a social networking service and website started in February 2004. Facebook users must register before using the site. Users may join user groups. These groups can be for a workplace, school or college, or other interest.Facebook as the most used social networking service by worldwide monthly active users.Facebook was started by Mark Zuckerberg with his college roommates and fellow computer science students Eduardo Saverin, Dustin Moskovitz and Chris Hughes.For More Information Please Visit At :-http://www.seoczar.com/social-media-marketing/.