After the early land rush and fast exponential growth of online social networking platforms, concerns about how data placed in online social networks may be exploited and abused have begun to appear among mainstream users. Social networking sites have responded to these new public sentiments by introducing privacy filters to their site, allowing users to specify which aspects of their profile are visible to whom. In this paper, we demonstrate that such an approach to privacy and informational self-determination is largely futile: as we form social relations and build networks with those alike us, much of who we are and what we do can be reconstructed from unhidden parts of the social graph.