To allow third-party websites to leverage social information maintained in a social networking system, a third-party website may include social information for a user in a web page provided by the third-party website. The social information is obtained from the social networking system. The web page provided by the third-party website includes a social context plug-in that causes a user's browser to obtain social information from a social networking system and to incorporate it within the web page. Customization rules are specified by the web page or by the third-party website to determine how the social information is aggregated and presented on the web page. Hence, the customization rules allow an operator of the third-party website to customize the social content displayed with the web page to provide more relevant information to social networking system users interacting with the third-party website.