1. A method comprising, by a computing device: accessing a social graph 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, the nodes comprising: a first node corresponding to a first user associated with an online social network; and a plurality of second nodes that each correspond to a concept or a second user associated with the online social network; receiving from the first user a first structured query comprising references to one or more selected nodes from the plurality of second nodes and one or more selected edges from the plurality of edges; and generating one or more query modifications for the first structured query, each query modification comprising references to one or more modifying nodes from the plurality of second nodes or one or more modifying edges from the plurality of edges.