1. A computer-implemented method comprising: receiving, at a first server system, information related to users of a social network site; determining, by the first server system, a graph for at least a portion of the social network from the received information, the graph comprising a plurality of nodes connected by directional links, where each of the nodes corresponds to a user that has a profile page on the social network, and where each of the directional links represents a user of the social network, represented by a node, having viewed at least an aspect of a profile page for another user, represented by another node; identifying first nodes from the plurality of nodes as including content associated with a particular subject of interest; seeding the identified first nodes with first scores, wherein the first scores indicate that first profile pages that correspond to the identified first nodes were positively identified as including content associated with the particular subject of interest; determining second scores for second nodes of the plurality of nodes, wherein the second scores indicate likelihoods that second profile pages associated with the second nodes contain content that is associated with the particular subject of interest, wherein the second scores are determined by propagating the first scores across the social graph to the second nodes based on one or more users who have viewed aspects of both i) one or more of the first profile pages for one or more of the first nodes and ii) one or more of the second profile pages for one or more of the second nodes, and wherein the one or more users correspond to one or more third nodes of the plurality of nodes that have directional links to both i) the one or more of the first nodes and ii) the one or more of the second nodes; and providing, by the first server system, the determined second scores for the second nodes.