The rapid development of the Internet has created new opportunities for teaching in general and it is our aim to show how the current evolution can best be exploited for crystallography education in particular. Currently, we can find a very large selection of media dedicated to crystallographic education extending from plain text and videos to the most elaborate forms of interactive simulations. However, due to the lack of criteria for ranking educational materials, it is difficult to select the most appropriate information for educational purposes. In this article, we propose a modular approach to the teaching of crystallography along the lines of the Kahn Academy in the field of mathematics. Each module can be an interactive application (applet), a short video or any other form of media which can be used by teachers and learners to illustrate the fundamental concepts of crystallography. This includes, among others, topics on the symmetry of periodic objects, diffraction phenomena, the Fourier methods of density calculations and the representation of structures depending on the physical or chemical phenomena that one would like to stress. The modular approach resides in the freedom given to the teachers in selecting the topics which are best suited according to their visions, needs and pedagogical aims.