Facebook is the biggest social networking site, with the largest number of users. Founded in 2004 as a site for students, soon became open to users of all countries and professions. Facebook requires the users to use their real names and real information, as opposed to nicknames present on other social networking sites. Users can exchange private messages, or write public messages on each other's 'wall', send gifts, share applications, update their status, write a blog and use the Faceboog Instant Messenger. One of the most important steps in the development of Facebook was to give access to the API, and allow users to create thousands of applications, games, and sets of gifts. Facebook puts much emphasis on privacy, so users can decide whether to make their profiles visible to everyone, or to friends only, they can also choose which sections are visible to which group.