15. A method, comprising: determining, by at least one computing device comprising a processor and a memory, that a search query string includes a first keyword describing an automobile; identifying, by the at least one computing device, a result set of automotive items from a catalog of items according to the first keyword, the result set of automotive items being compatible with the automobile; ranking, by the at least one computing device, the result set of automotive items according to a first set of customer behavior data indicating selections of automotive items by a plurality of customers who also searched for automotive items compatible with the automobile, wherein ranking the result set of automotive items is configured to surface in the result set a particular automotive item that is associated with a defect in the automobile; inferring, by the at least one computing device, a second keyword according to the automobile and a second set of customer behavior data that indicates a plurality of sales of automotive items to the plurality of customers; determining, by the at least one computing device, a non-application keyword specified in the search query string; and identifying, by the at least one computing device, a subset of the result set of automotive items according to the inferred second keyword and the non-application keyword.
15. A method, comprising: determining, by at least one computing device comprising a processor and a memory, that a search query string includes a first keyword describing an automobile; identifying, by the at least one computing device, a result set of automotive items from a catalog of items according to the first keyword, the result set of automotive items being compatible with the automobile; ranking, by the at least one computing device, the result set of automotive items according to a first set of customer behavior data indicating selections of automotive items by a plurality of customers who also searched for automotive items compatible with the automobile, wherein ranking the result set of automotive items is configured to surface in the result set a particular automotive item that is associated with a defect in the automobile; inferring, by the at least one computing device, a second keyword according to the automobile and a second set of customer behavior data that indicates a plurality of sales of automotive items to the plurality of customers; determining, by the at least one computing device, a non-application keyword specified in the search query string; and identifying, by the at least one computing device, a subset of the result set of automotive items according to the inferred second keyword and the non-application keyword. 17. The method of claim 15 , wherein the customer behavior data further indicates a plurality of sales of items to the plurality of customers.