The paper discusses the advantages of Virtual Campus, a platform integrating authoring, fruition and validation modules, where flexibility and personalization of the whole system are main goals. To ease the authoring activities, Virtual Campus leverages both the reusability of existing courses - while building new ones - and a customization process that allows to adapt an existing course to different situations. To achieve course and material content reusability a model has been developed that - with the aid of metadata - permits to store, classify, and browse didactical materials, making them available for flexible learning paths. A run-time infrastructure has been developed that can drive a student along a learning path previously designed by the teacher. A workflow management system manages every student's state of advance, allowing path customization. Finally a set of monitoring tools assist the students during their learning activities providing both suggestions to the students and feed-back to the teachers. Isolated and cooperative work sessions, tutored and untutored participations, virtual and "real" presence in an extended or restricted study group, synchronous and asynchronous communications have been studied for testing the global system.
