The document summarizes a study on how trust in Facebook and trust in friends affects privacy protection behavior on social networks. The study found that trust in friends and trust in Facebook are two independent factors. Participants reported much higher trust in their friends compared to Facebook. Low trust in friends led to more privacy protection behaviors like deleting comments and pictures, while low trust in Facebook only influenced withholding of initial profile information. The large number of "friends" on social networks poses risks as people may not be able to predict the behavior of distant connections. General privacy attitudes did not predict specific Facebook behaviors, though specific Facebook privacy concerns also did not influence protection.