4. The computer-readable medium of claim 3 , further comprising the step of displaying as part of the re-ranked search results an identifier of a particular source document, one or more tags associated with the search request, and the tag scores for the particular source document corresponding to the tags associated with the document search request.
3. The computer-readable medium of claim 1 , wherein the document retrieval request is a document search request submitted to a search engine, further comprising the steps of: retrieving initial search results from the search engine ranked at least in part based on the tag-mediated content quality scores in the content quality information database; comparing terms in the document search request to tags stored in the content quality information database; identifying one or more relevant tags associated with the search request; re-ranking the initial search results based on highest relative tag scores for the tags associated with the document search request in a re-ranked priority order; and displaying the re-ranked search results comprising identifiers of electronic source documents among the search results in the re-ranked priority order.