4.1 Modelling user interests The approach chosen in CRUMPET is especially suitable for information brokerage (Nick 2001). The model of interest is based on a domain taxonomy, i.e. a taxonomy of tourism-related services for CRUMPET. The domain model is a domain-specific, structured set of concepts and attributes describing a tourist service. The user interest is seen as a function mapping these concepts and attributes to the probability p that the user is interested in such services (see figure 1).