The highly developed Nordic telecom market has undergone enormous changes in the past decade. From dealing with a single customer group (fixed line only), we now face a much more sophisticated market with three coexisting groups: fixed line only; both fixed line and mobile; and wireless 'mobile only'. TNS Nordic Telecom Index gives an overview of end-users in Norway, Denmark, Finland and Sweden. New methods have been developed for gathering information from the 'mobile only' group.The paper compares this new and growing group with traditional groups. Finally the strategic marketing implications of this new knowledge are explored.