Privacy is not easy to define because it can be applied to any sphere of our life. However, I think a comprehensive definition of privacy was given by Westin in 1967. He defined privacy as, “the claim of individuals, groups, or institutions to determine for themselves when, how, and to what extent information about them is communicated to others” (Lee, 2002). In other words, we should be able to control information about us. This definition is relevant because it also defines informational privacy which is the main issue on Facebook. David Friedman, an editor of the book “The Right to Privacy”, says that physical privacy increased nowadays and informational privacy decreased because people do not have an ability to see with their own eyes how their personal information is used. In addition, he says that what matters for him is not whether information exists online, but whether other people can have an access to it (Paul, Miller, Paul, 2000). This may mean that violation of informational privacy, awareness and inappropriate usage of a Facebook user’s personal information by other people, affect our daily life or physical privacy causing many unwanted issues such as stress, scandals, dismissal, or problems in private life, etc. In order to understand why Facebook cannot provide informational privacy which also affects our physical privacy, we should consider the main reasons of it.