The popular social networking website Facebook exposes a "public view" of user profiles to search engines which includes eight of the user's friendship links. We examine what interesting properties of the complete social graph can be inferred from this public view. In experiments on real social network data, we were able to accurately approximate the degree and centrality of nodes, compute small dominating sets, find short paths between users, and detect community structure. This work demonstrates that it is difficult to safely reveal limited information about a social network.