13. A system, comprising: a processor; a data repository that includes a computer-implemented bipartite graph, wherein the bipartite graph includes a first set of nodes that represent queries, a second set of nodes that represent URLs, and weighted edges that represent relationships between queries and URLs, wherein the edges are weighted based at least in part upon a number of user selections of URLs given particular queries, wherein the first set of nodes includes a first node that represents a first query and a second node that represents a second query; a memory that comprises a plurality of components that are executed by the processor, the plurality of components comprising: an analyzer component that analyzes queries submitted by users and corresponding URLs selected by the users, wherein the queries include the first query and the second query, and wherein the analyzer component initiates a random walk at the first node in the bi-partite graph and counts a number of steps taken during the random walk until the random walk reaches the second node in the bipartite graph, the analyzer component determining that the first query and the second query are substantially similar based at least in part upon the number of steps taken during the random walk; and a correlator component that, responsive to the analyzer component determining that the first query and the second query are substantially similar, generates correlation data that indicates that the first and second queries are substantially similar.
13. A system, comprising: a processor; a data repository that includes a computer-implemented bipartite graph, wherein the bipartite graph includes a first set of nodes that represent queries, a second set of nodes that represent URLs, and weighted edges that represent relationships between queries and URLs, wherein the edges are weighted based at least in part upon a number of user selections of URLs given particular queries, wherein the first set of nodes includes a first node that represents a first query and a second node that represents a second query; a memory that comprises a plurality of components that are executed by the processor, the plurality of components comprising: an analyzer component that analyzes queries submitted by users and corresponding URLs selected by the users, wherein the queries include the first query and the second query, and wherein the analyzer component initiates a random walk at the first node in the bi-partite graph and counts a number of steps taken during the random walk until the random walk reaches the second node in the bipartite graph, the analyzer component determining that the first query and the second query are substantially similar based at least in part upon the number of steps taken during the random walk; and a correlator component that, responsive to the analyzer component determining that the first query and the second query are substantially similar, generates correlation data that indicates that the first and second queries are substantially similar. 14. The system of claim 13 , wherein the analyzer component computes one of hitting time between the first node and the second node, commute time with respect to the first node and the second node, or meeting time between the first node and the second node.