Abstract. The purpose of this article is to propose a scalable, topologically and traffic-wise self-adapting approach to a publish/subscribe paradigm for supporting event-based applications on a wide-area network. Large event systems requiring an efficient group communication as well as anonymity of particular peers tend to be fully decoupled. The publish/subscribe paradigm provides this requirement which enlarges a range of dimensions involving such system. There are two main approaches, namely topic-based and content-based publish/subscribe. The advantages and disadvantages of the approaches are often complementary one to another. This article presents a method of improving efficiency of large-scale systems while preserving scalability by involving cooperation of topic-based and content-based techniques. 1 The Publish/Subscribe Paradigm The publish/subscribe paradigm is a loose communication scheme for modelling the autonomous interaction among participants in event systems and intr...