5. The method of claim 4 , wherein each edge connecting a third node to a first or second node has a particular attribute.
4. The method of claim 1 , further comprising accessing a social graph comprising a plurality of nodes and a plurality of edges connecting the nodes, each edge between two nodes representing a single degree of separation between the two nodes, the plurality of nodes comprising: a first node corresponding to a first user of an online social network; a plurality of second nodes corresponding to a plurality of second users of the online social network, respectively; and a plurality of third nodes corresponding to a plurality of locations, respectively.