15. A system, comprising: at least one computing device; and a network site classification engine in the at least one computing device, the network site classification engine comprising: logic that computes a plurality of similarities between a first plurality of search queries and individual ones of a second plurality of search queries, the first plurality of search queries returning an unclassified network site and the second plurality of search queries returning a plurality of classified network sites, individual ones of the classified network sites having a respective category, wherein the plurality of similarities are based at least on a query importance comprising a click through and the query importance is associated with a search query in the first plurality of search queries and the second plurality of search queries; and logic that classifies the unclassified network site into the respective category of one of the classified network sites based at least in part on the plurality of similarities.
15. A system, comprising: at least one computing device; and a network site classification engine in the at least one computing device, the network site classification engine comprising: logic that computes a plurality of similarities between a first plurality of search queries and individual ones of a second plurality of search queries, the first plurality of search queries returning an unclassified network site and the second plurality of search queries returning a plurality of classified network sites, individual ones of the classified network sites having a respective category, wherein the plurality of similarities are based at least on a query importance comprising a click through and the query importance is associated with a search query in the first plurality of search queries and the second plurality of search queries; and logic that classifies the unclassified network site into the respective category of one of the classified network sites based at least in part on the plurality of similarities. 17. The system of claim 15 , wherein the plurality of similarities are based at least on a query popularity computed as a function of a query frequency divided by a query volume.