Despite the fact that several integrated development methods for web information systems (WISs) have been proposed, quality assurance for such systems has hardly been addressed. In this paper some quality criteria are postulated and investigated by combining semi-formal and formal methods. On a high level of abstractions WISs can be described by abstract locations and transitions between them. These so-called story spaces can be formalised using Abstract State Machines (ASMs), which permit to verify, whether user-tailored versions are compatible with user preferences. Furthermore, ASMs provide a framework for refinement, which permits the integration of story spaces with extended views on databases. This leads to further proof obligations for consistency that can be formalised in the logic associated with ASMs.