This chapter discusses the use of formal techniques and formal verification tools to ensure privacy-aware social networking; hence users of social-networking sites can predict what the consequences of updating their privacy settings are. A formal methods approach is presented for modeling and comparing social-network privacy policies, and for checking whether a user’s privacy policy can coexist with other policies within a social networking site. The authors present the Poporo tool implementing the approach. Poporo builds on a predicate calculus definition for social networking written in B that models social network content, people in the network, friendship relations, and privacy policies that are modeled as permissions to access content. Several examples of privacy-awareness social networking are also shown using Poporo.