The paper presents a methodology to design and to develop personalizable educational content to be used by learning communities on the Web. As the cost of design and creation of educational materials for web-based courses is normally expensive and time consuming, there is an obvious advantage in exchanging course material between educators involved in the same field. To this end we are claiming that other than the adoption of re-use methodologies, a valuable saving is obtained by realizing content that best fits the actual needs of different students engaged in diverse learning scenarios. A methodology that couples re-use techniques with personalization methods is discussed and a layered modelling process is proposed. A system based on this model is considered, and some of its peculiar implementation aspects are highlighted. In particular, focus is placed on the benefits of using XML technology as a straighforward solution to our modelling requirements.