Current Social Web applications provide users with means to easily publish their personal information on the Web. However, once published, users cannot control how their data can be accessed apart from applying generic preferences (such as “friends” or “family”). In this paper, we describe how we enable finer-grained privacy preferences using the Privacy Preference Ontology (PPO); a light-weight vocabulary for defining privacy settings on the Social Web. In particular, we describe the formal semantic model of PPO and also present MyPrivacyManager, a privacy preference manager that let users (1) create privacy preferences using the aforementioned ontology and (2) restrict access to their data to third-party users based on profile features such as interests, relationships and common attributes.