Social networking sites vary in the levels of privacy offered. For some social networking sites like Facebook, providing real names and other personal information is encouraged by the site(onto a page known as a ‘Profile‘). These information usually consist of birth date, current address, and telephone number(s). Some sites also allow users to provide more information about themselves such as interests, hobbies, favorite books or films, and even relationship status. However, there are other social network sites, such as Match.com, where most people prefer to be anonymous. Thus, linking users to their real identity can sometimes be rather difficult. Nevertheless, individuals can sometimes be identified with face re-identification. Studies have been done on two major social networking sites, and it is found that by overlapping 15% of the similar photographs, profile pictures with similar pictures over multiple sites can be matched to identify the users.[1]
For sites that do encourage information disclosure, it has been noted that majority of the users have no trouble disclosing their personal information to a large group of people.[1] In 2005, a study was performed to analyze data of 540 Facebook profiles of students enrolled atCarnegie Mellon University. It was revealed that 89% of the users gave genuine names, and 61% gave a photograph of themselves for easier identification.[1] Majority of users also had not altered their privacy setting, allowed a large number of unknown users to have access to their personal information (the default setting originally allowed friends, friends of friends, and non friends of the same network to have full view of a user‘s profile). It is possible for users to block other users from locating them on Facebook, but this must be done by individual basis, and would therefore appear not to be commonly used for a wide number of people. Most users do not realize that while they make