38. The system of claim 17 , wherein determining a navigation score for the revised query comprises: determining a click-through rate for each resource identified by a search engine in response to the revised query, the click-through rate being a rate at which search results generated in response to the query and referencing the resource were selected; and wherein the navigation score threshold is a click-through rate threshold.
38. The system of claim 17 , wherein determining a navigation score for the revised query comprises: determining a click-through rate for each resource identified by a search engine in response to the revised query, the click-through rate being a rate at which search results generated in response to the query and referencing the resource were selected; and wherein the navigation score threshold is a click-through rate threshold. 39. The system of claim 38 , wherein identifying the navigational resource for the revised query comprises identifying as the navigational resource the resource having a click-through rate that exceeds the click-through rate threshold.