There are many different definitions and aspects of privacy. This chapter is
concerned with privacy defined as: selective control over who accesses personal
information, including contact information and personal communication, and control
over the contexts in which the information can be used (Altman 1976;
Nissenbaum 2004). This excludes privacy in the sense of seclusion, which is not
relevant to social activities. Control over the contexts in which information is used is
important because of the ease with which web content can be recycled or forwarded.