E-commerce has become a common activity among many people. Although widely used, the interfaces which users communicate with e-commerce systems are still at an early stage of development in terms of intelligence and user-friendliness. Unobtrusiveness is recognized as one of the most important desired attributes of an intelligent and friendly interface. In this paper we describe our work on an information architecture to minimize obtrusiveness. A layered information architecture supported by a structured user profile model is described in the paper. As example scenario is presented to clarify the new architecture and the development of a cost model for measuring the level of obtrusiveness is discussed