Abstract
Social networking sites have sprung up and become a hot issue of current society. In spite of the fact that these sites provide users with a variety of attractive features, much to users' dismay, however, they are prone to expose users' private information. In this paper, we propose an approach which addresses the problem of collaboratively deciding privacy policies for, but not limited to, shared photos. Our approach utilizes trust relations in social networks and combines them with Condorcet's preferential voting scheme. We study properties of our trust-augmented voting scheme and develop two approximations to improve its efficiency. Our algorithms are compared and justified by experimental results, which support the usability of our trust-augmented voting scheme.