The purpose of this paper is to introduce an interpretation model for the deployment of new media in didactics, taking inspiration from theories coming both from Didactics and Semiotics. State of the art experiences are analysed, in order to evaluate and settle novelties and limits in an adequate context. Finally, the project of a new didactic system is described. This system takes advantage from the expert systems technology and from the latest media format research (MPEG-4 and MPEG-7). It exploits the potential of the new media in terms of enhanced dynamic hypertext navigation and interactivity through the use of semantic data.