Access control policies are notoriously difficult to configure correctly, even people who are professionally trained system administrators experience difficulty with the task. With the increasing popularity of online social networks (OSN) users of all levels are sharing an unprecedented amount of personal information on the Internet. Most OSNs give users the ability to specify what they share with whom, but the difficulty of the task raises the question of whether users' privacy settings match their sharing intentions. We present the results of a study that measures sharing intentions to identify potential violations in users' real Facebook privacy settings. Our results indicate a serious mismatch between intentions and reality: every one of the 65 participants in our study had at least one confirmed sharing violation. In other words, OSN users' are unable to correctly manage their privacy settings. Furthermore, a majority of users cannot or will not fix such errors.