Facebook is the largest social networking site in the world. Founded in 2004 by Mark Zuckerberg, the site had over 500 million worldwide users as of October 2010, and has long since surpassed all of its social networking peers. Facebook allows users to create a profile and join various types of self-contained networks, including college-wide, workplace, and regional networks. The site includes a wide array of tools that allow users to connect and interact with other users, including messaging, groups, photo-sharing, and user-created applications.