2. The method of claim 1 , wherein determining the second resource score of the query comprises: initiating a search of only a proper subset of the second resources, and receiving, in response to the search, second search scores of second resources in the proper subset of second resources, each second search score corresponding to a second resource and being indicative of the relevance of the second resource to the query; and determining, from the second search scores of the second resources, the second resource score for the query.
2. The method of claim 1 , wherein determining the second resource score of the query comprises: initiating a search of only a proper subset of the second resources, and receiving, in response to the search, second search scores of second resources in the proper subset of second resources, each second search score corresponding to a second resource and being indicative of the relevance of the second resource to the query; and determining, from the second search scores of the second resources, the second resource score for the query. 3. The method of claim 2 , wherein determining, from the second search scores of the second resources, the second resource score for the query comprises: determining a first number of web page resources that include a second resource in the proper subset of second resources that has a corresponding second search score that meets second search score threshold; determining a second number of web page resources that include at least one of the second resources in the proper subset of second resources; and determining the second resource score based on a ratio of the first number to the second number.