1. A computer-implemented method, the method comprising: tracking, by using a computer, search activities of actual search engine users over a plurality of different search engines; programmatically analyzing the tracked search activities to generate statistical data regarding a plurality of unique search queries used by a plurality of users of the plurality of different search engines to locate and access a particular document, said statistical data encompassing user search activities over the plurality of different search engines, wherein the programmatically analyzing is performed by a computer system; using at least the statistical data regarding the plurality of unique search queries to control automatic selection of advertisements to include in the particular document, wherein the statistical data identifies the search queries used the most frequently over the plurality of different search engines to locate the document, wherein the using at least the statistical data further comprises: determining a data variance between content of the particular document and at least one search query used to locate the particular document, wherein the at least one search query was previously not identified with the content of the particular document, wherein the automatic selection is thereafter based at least partly on the at least one search query; determining whether most referrals or a mathematically significant number of referrals from a particular search engine for the particular document correspond to a search query that is algorithmically relevant to the particular document; when the most referrals or the mathematically significant number of referrals from the particular search engine for the particular document are based on search queries that are not algorithmically relevant, providing advertising based on the search query used in response to a request for the particular document arising from use of that particular search engine and to a predicted user expectation of content, as determined by analyzing the tracked search activities, wherein the advertising is otherwise irrelevant to the particular document; and otherwise, providing advertising that is algorithmically determined to be relevant to the particular document.