The tremendous impact of the world wide web (WWW) on our society has, to a large extent, been made possible by two factors. The first is that the information on the Web is composed of the same elements as are traditional documents, i.e. text and images. The second factor is that the principles for accessing information and for navigating through it are universal. The information we want to disseminate can be accessed by anyone using any browser on any type of computer, not just by the specific group of users that have installed a particular software package. This is made possible by strict standardisation of the types of information and of the ways of interaction. However, this imposes restrictions on the kind of information that can be used, and causes the level of interactivity to be fairy low.