Abstract: Systems and methods for processing metadata are described. An application makes available a social networking application with an application programming interface (API) configured to receive social data from a social networking site for a user. The application publisher system receives advertisement metadata from a first system and social data from a social networking site system. Based at least in part on the advertisement metadata and the social data, the application publisher system identifies a suitable advertisement and transmits a request for the identified advertisement to the first system, wherein the social data for the user is not transmitted to the first system, to thereby retain the privacy of the user. The identified advertisement is then electronically provided to the user.