Guarding a Walled Garden — Semantic Privacy Preferences for the Social Web

With increasing usage of Social Networks, giving users the possibility to establish access restrictions on their data and resources becomes more and more important. However, privacy preferences in nowaday’s Social Network applications are rather limited and do not allow to define policies with fine-grained concept definitions. Moreover, due to the walled garden structure of the Social Web, current privacy settings for one platform cannot refer to information about people on other platforms. In addition, although most of the Social Network’s privacy settings share the same nature, users are forced to define and maintain their privacy settings separately for each platform. In this paper, we present a semantic model for privacy preferences on Social Web applications that overcomes those problems. Our model extends the current privacy model for Social Platforms by semantic concept definitions. By means of these concepts, users are enabled to exactly define what portion of their profile or which resources they want to protect and which user category is allowed to see those parts. Such category definitions are not limited to one single platform but can refer to information from other platforms as well. We show how this model can be implemented as extension of the OpenSocial standard, to enable advanced privacy settings which can be exchanged among OpenSocial platforms.