11. A non-transitory computer storage medium storing instructions which, when processed by one or more processors, cause: generating a plurality of navigation trails based on an ordered sequence of navigational activities performed by a plurality of users; grouping the plurality of navigation trails into a plurality of navigation trail groups based on original queries with which navigation trails in the plurality of navigation trails begin; for at least a particular navigation trail group of the plurality of navigation trail groups, determining one or more uniform resource locators (URLs) or revised queries that occur in at least a specified proportion of navigation trails in the particular navigation trail group; generating a search results page based at least in part on the one or more URLs or revised queries that occur in at least a specified proportion of navigation trails in the particular navigation trail group; and storing the search results page on a computer-readable storage medium; wherein at least one navigation trail in the particular navigation trail group contains at least one URL or revised query that another navigation trail in the particular navigation trail group does not contain.
15. The non-transitory computer storage medium of claim 11 , wherein generating the plurality of navigation trails comprises: for each search result that a particular user of the plurality of users selected from a set of search results that an Internet search engine returned to the particular user, determining whether user input that expressed the particular user's interest in a resource to which the search result refers was received from the particular user before a moment that the particular user navigated away from that resource; determining whether particular user input that expressed the particular user's interest in a particular resource to which a particular search result refers was received from the particular user before a moment that the particular user navigated away from that particular resource; and in response to determining that the particular user input was received from the particular user before the moment that the particular user navigated away from the particular resource, ending a particular navigation trail of the plurality of navigation trail with a URL of the particular search result.