Adaptivity in web applications raises several concerns. One demands it to be decoupled from the actual application and at the same time wants to use very domain-specific terms for dividing the audience into groups. Two current trends, aspect-oriented programming and semantic web technologies, fit these requirements like a glove. In this paper, we present the Amacont web modeling framework and use it as an example of how to extend such a framework to make use of these powerful technologies. The underlying concepts, however, can be applied to the modeling of adaptivity in general.