Many information systems are used in a problem solving context. Examples are travel planning systems, catalogs in electronic commerce, or agenda planning systems. They can be made more useful by integrating problem-solving capabilities into the information systems. This poses the challenge of scalability: when hundreds of users access a server at the same time, it is important to avoid excessive computational load. In this paper, we present an approach, called reality, that allows to significantly extend the reach of electronic commerce in travel. Our application addresses in particular the challenge of modeling customers’ personal preferences and providing solutions that are tailored to just those preferences. In contrast to existing technology, which allow to optimize only a small and predefined set of preferences, our tool allows a wide variety that can accurately model the preferences of different customers. Keywords catalogs, direct manipulation, soft constraint satisfaction,...