In order to optimize the information retrieval and adaptation facilities inside an e-learning system, there is necessary to improve accessibility and to correlate the educational materials, the users and the information. For this purpose, we present a semantic Web-based modeling approach for the materials annotations and user competences profile, based on the same domain ontology set. The ontologies constitute thus the binder between the materials and users, and we illustrate how their reasoning support contributes to the efficiency improvement of the search and adaptive Web services. As illustrative example, we present our developed I*Teach Web repository of educational scenarios.