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.Privacy concerns with social networking services is a subset of data privacy, involving the right of mandating personal privacy concerning storing, re-purposing, provision to third parties, and displaying of information pertaining to oneself via the Internet.Social network security and privacy issues result from the astronomical amounts of information these sites process each day. candidate at Berkeley, made small headlines last year when she exposed a potentially devastating hole in the framework of Facebook's third-party application programming interface (API).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.
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.
According to Evan, the answer to the question is not likely to be found, because a better regulated API would be required for Facebook "to break a lot of applications, [especially when] a lot of companies are trying to make money off [these] applications".
Felt agrees with her conclusion, because "there are marketing businesses built on top of the idea that third parties can get access to data and user information on Facebook".
The advent of the Web 2.0 has caused social profiling and is a growing concern for internet privacy.
These social networking sites have seen a boom in their popularity starting from the late 2000s.