Geosocial networks (GSNs) are a popular extension of the growing online social networking phenomenon. The wealth of personal information voluntarily revealed by subscribers, however, exposes them to a wide range of privacy vulnerabilities. In this article we describe basic GSN features and show how external attackers can exploit them in order to gain access to sensitive user information. We introduce several properties that need to be satisfied by a viable, privacy preserving GSN solution. We survey the body of work addressing GSN attacks and privacy issues, and compare their ability to satisfy the crystallized properties. Finally, we propose several open research directions.