1. A method comprising: receiving, by one or more processors associated with one or more computing systems, a request from a first user of a social network environment for at least one item of content, wherein the request comprises one or more characters of a character string received as the first user enters the character string at a client computing system into a graphical user interface, and wherein the social network environment comprises a social graph comprising a plurality of nodes and a plurality of edges connecting the nodes, one or more of the nodes each being associated with one or more items of content, the plurality of nodes comprising: a first node corresponding to the first user; and a plurality of second nodes that each correspond to a concept or a second user of the social network environment; identifying, by the one or more processors, one or more matching nodes of the plurality of nodes based on the character string of the request received from the first user, each matching node being associated with an item of content that matches at least a portion of the character string of the request received from the first user; determining, by the one or more processors, one or more nodes to recommend that are conceptually relevant to one or more of the matching nodes that are each associated with an item of content that matches at least a portion of the character string of the request received from the first user, each recommended node being identified at least in part on a relevance score for the recommended node with respect to the one or more of the matching nodes calculated by the one or more processors based on connections in the social graph between the node and one of the matching nodes, each recommended node having a relevance score greater than a threshold relevance score; and sending, by the one or more processors, in response to the request received from the first user, one or more references corresponding to the one or more recommended nodes, respectively, for presentation to the user as the user enters the character string of the request received from the first user into the graphical user interface, the presentation of the references to the user enabling the user to select the references to interact with the recommended nodes.