The World-Wide-Web is a ubiquitous, global tool, used for nding information, communicating ideas, carrying out distributed computation, and conducting business. The web is highly dynamic in the quantity and nature of the information that it encompasses. Thus, there is a need to understand how the information content and usage of the web change, and to develop techniques for organising and processing information which handle and exploit its inherent dynamics. Access to the web may be from a variety of devices and interfaces, di erent users at di erent locations, and at varying times. There is thus also a need for techniques which dynamically adapt information presentation to the mode of access and to the speci c user requirements.