1. A method comprising: receiving, by one or more computing devices, a query associated with a first user of a social-networking system, the query comprising a first user attribute, the social-networking system comprising a graph that comprises a plurality of nodes and edges connecting the nodes, at least one node in the graph corresponding to the first user; identifying, by one or more of the computing devices, a plurality of second users of a third-party-application system that is external to the social-networking system, each of the second users of the third-party-application system being associated with a user attribute matching the first user attribute of the query; identifying, by one or more of the computing devices, one or more third users of the social-networking system, for each of the third users at least one node in the graph corresponding to the third user, at least one of the nodes corresponding to the first user and at least one of the nodes corresponding to a third user being connected to each other by an edge; comparing, by one or more of the computing devices, each of the second users of the third-party-application system with each of the third users of the social-networking system to identify one or more of the second users who match the third users based on the first user attribute of the query; and providing, by one or more of the computing devices, a search results page responsive to the receive query, the search results page comprising information associated with each of the second users of the third-party-application system who match the third users.