Differences in demographic data regarding physicians and patients in the US or abroad using a medically oriented Internet information service.

Since early 1994 we have offered access to the National Cancer Institute's guidelines for current cancer therapy to physicians via WWW. These guidelines, which are provided by the NCI in accordance with the rules for evidence-based medicine, are accompanied by general information for non-professionals. Since we launched this comprehensive cancer-related WWW information service in 1994, more than about 1 million customers retrieved documents from our CancerNet service via WWW (http://www.meb.uni-bonn.de/cancernet/). From user surveys in 1996, 1997, 1998, and 1999, we obtained demographic data about our users, their interests, and their opinions regarding this information service. The following analysis shows how this service was used over the years and includes some unexpected differences between users in the US, Europe, and developing countries.