2. The method of claim 1 , further comprising: accessing, by one or more computing devices, a graph data structure comprising a plurality of nodes and a plurality of edges connecting the nodes, each of the edges between two of the nodes representing a single degree of separation between them.
3. The method of claim 2 , wherein the plurality of nodes comprises a first node corresponding to the first user and one or more second nodes corresponding to the one or more second users of the social-networking system, respectively.