Increasing ease of access to the Internet is making it feasible for geographically dispersed communities to work closely together, coordinating their activities through electronic mail, digital document archives, and access to remote computing facilities. This article reports on practical experience of knowledge management for a number of communities and projects. It gives an overview of the technologies available, their accessibility, ease of use and impact on collaborative activities. It focuses on the practical problems that arise, the limitations of existing technologies, and how these may be overcome. Examples are given of projects encompassing a range of multimedia digital technologies from list servers, through World Wide Web document archives, production in a few days of CD-ROMs containing movies and digitized foils and documents giving a complete account of working meetings, to active documents that are themselves expert systems.