16. A computer-readable memory device, comprising: a plurality of computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to: identify a group of search result documents that are responsive to a search query; determine a measure of staleness of a search result document in the group of search result documents; determine whether a stale document is preferred for the search query, the computer-executable instructions to determine whether a stale document is preferred for the search query including a plurality of computer-executable instructions to: determine, based on analyzed past selections of documents, whether a first document was previously selected over a second document in a set of search results relating to the search query or a similar search query, where the first document is ranked lower than the second document, and where the first document is older than the second document, and identify the search query as a search query for which a stale document is preferred when the first document, that was ranked lower than the second document, was previously selected over the second document in the set of search results relating to the search query or the similar search query; generate a score for the search result document based on: the measure of staleness of the search result document, and whether a stale document is preferred for the search query; and rank the search result document with regard to at least one other search result document, of the group of search result documents, based on the generated score.
18. The computer-readable memory device of claim 16 , where the measure of staleness of the search result document is based on at least one of: a creation date associated with the search result document, anchor growth associated with the search result document, a measure of change of content associated with the search result document, a rate of growth of a quantity of links to the search result document, or a rate of growth of a quantity of links from the search result document.