Privacy in Online Social Networks

Online Social Networks (OSNs) have become part of daily life for millions of users. Users building explicit networks that represent their social relationships and often share a wealth of personal information to their own benefit. The potential privacy risks of such behavior are often underestimated or ignored. The problem is exacerbated by lacking experience and awareness in users, as well as poorly designed tools for privacy-management on the part of the OSN. Furthermore, the centralized nature of OSNs makes users dependent and puts the Service Provider in a position of power. Because Service Providers are not by definition trusted or trustworthy, their practices need to be taken into account when considering privacy risks. This chapter aims to provide insight into privacy in OSNs. First, a classification of different types of OSNs based on their nature and purpose is made. Next, different types of data contained in OSNs are distinguished. The associated privacy risks in relation to both users and Service Providers are identified, and finally relevant research areas for privacy-protecting techniques are discussed. Clear mappings are made to reflect typical relations that exist between OSN type, data type, particular privacy risks and privacy-preserving solutions.