29. The computer-based system of claim 26 , further comprising a query-results region including: one or more interactive control features for invoking display of corresponding search-result documents; and at least one interactive control feature for identifying and invoking display of a search-result document deemed to be a duplicate of at least another of the search-result documents.
26. The computer-based system of claim 25 further comprising a graphical user interface comprising: a query-definition region on a display device, the region including one or more interactive control features for facilitating user definition of a query; and at least one interactive control feature, within the query-definition region, for enabling a user to select whether search results provided in response to the query are to identify documents determined to have substantial duplicate content.