Presents a report of a survey, based on case studies, of current practice in the building and use of taxonomies, with particular emphasis on corporate taxonomies to support enterprise information portals. Of the 22 case studies, six were designated as "core" and four are discussed in this paper: British Broadcasting Corporation, Glare Wellcome, Microsoft, and Unilever. Discusses key factors leading enterprises to consider the building of corporate taxonomies and describes the uses of taxonomies, principally as, inter alia, a source of authority for tagging, to aid navigation, to support search engines, as knowledge maps, and as a depository of enterprise retrieval languages. Key findings are presented.