The essence of privacy does not lie in the seclusion from others，but in the choice of the time，place and person to whom to disclose. The right to personal information is the right of protecting personal space and life from spying，theft，tracking，digging，spreading and exposure. The right to privacy may not disappear even if a person enters a public place，what counts is the degree of reasonable privacy expectation. In cyberspace age，it’s necessary to distinguish mass media and social media，the former is aimed to serve the public，while the latter is designed to serve individuals’ presentation. The user may have reasonable privacy expectations of different degrees to social networking，therefore the service provider has duty of security.