The information to be shared by the SUs in MSN is closely related to the social context, including the profiles of neighboring SUs and the service of neighboring LSPs. For example, in a shopping mall, people surrounded by clothing stores expect to share and receive discount information on clothes; in a conference, participants are willing to discuss research topics and projects with other research scholars. Based on the social context, the disclosed personal information can be used to identify an SU’s behavior at different levels. In the previous example, if a research scholar discusses research topics in a shopping mall, his behavior is easily distinguished from nearby customers. Thus, to achieve privacy preservation, the social context should be considered in MSN communication protocol design. Most existing privacy- preserving profile matching protocols [4, 5] aim at minimizing profile information disclosure but neglect the relations between the disclosed information and the social context. From [6], it is shown that the anonymity variation of an SU depends on the profile information of its nearby SUs. Thus, the effectiveness of profile matching protocols in terms of privacy preservation needs to be further validated in different social contexts. Exploring practical social contexts and proposing effective protocols for specific social contexts is an important research direction.