Recommender systems can offer an approach to alleviating privacy settings usability issues that users (data owners) face on shared content platforms such as social media. These social media platforms raise an example of shared data belonging to different data owners that oftentimes is composed in the form of joint data such as shared blogs, posted content, forums, or chatrooms. Oftentimes users in these contexts have varying privacy preferences, as discussed in Chap. 5 , but are not always aware of the implications of their personal privacy preferences on collective privacy. Furthermore, matching usability with privacy provision is a challenging problem.