The growing role of online marketing in advertising and public relations and in shaping public opinion must be seen not only from the aspects of cost, achieved audience and ease of use, but also from the psychological, historical aspects of communication. It should be borne in mind that the fundamental principles of communication science are universally applicable in all marketing sectors and will therefore apply irrespective of the new trends in the sector. In order to be able to predict and respond appropriately to developments in digital marketing, it is necessary to understand the definition of digital marketing.