1. A method implemented by a system of one or more computer processors, the method comprising: receiving, at the system, machine-readable information characterizing a first user selection of a first search result that was identified by a search engine as responsive to a first search query; receiving, at the system, machine-readable information characterizing a second user selection of a second search result that was identified by a search engine as responsive to a second search query; determining, by the system, that breadth of the first search query is larger than breadth of the second search query; and recording, in response to the determination, a characterization of the second user selection of the second search result as more strongly indicative of popularity than the first user selection of the first search result, the characterization being recorded in a machine-readable popularity database that stores measures of popularity.