3. The method of claim 1 , wherein: the physical object is a book; and the content of the second document identifies the physical object with an ISBN number and the content of the particular document identifies the physical object with the ISBN number.
1. A computer-implemented method comprising: providing, by a computing system, a first query to a first search engine for searching a first corpus of documents; receiving, by the computing system and from the first search engine, a plurality of first search results that are responsive to the first query, each first search result corresponding to a first result document, each first search result being associated with a respective ranking among the first search results; and for at least a particular search result that corresponds to a particular document and that is in the plurality of first search results, performing the following: identifying, by the computing system, second relevance data that is indicative of a second search result's popularity as having been selected by a population of users as a result for a second query that is identical to the first query or similar to the first query, the second relevance data being identified based on the second search result corresponding to a second document that contains content that identifies a physical object that is also identified by content in the particular document; and determining, by the computing system, a new ranking for the particular search result among the plurality of first search results based on the particular search result's ranking and the second relevance data that is indicative of the second search result's popularity as having been selected by the population of users as the result for the second query, wherein determining the new ranking for the particular search result is further based upon first relevance data that is indicative of the particular search result's popularity as having been selected by a first population of users as a result for the first query, wherein determining the new ranking for the particular search result further comprises a weighting of the first relevance data and the second relevance data, and wherein the weighting favors the first relevance data as selections of the particular search result as a result for first query increase.