For a long time one has been convinced that the goal of science communication is to inform the general public. Democratic motives formed the basis of this conviction and the deficiency model acted as the theoretical framework. However, big surveys like the Eurobarometer have shown that it is difficult to reach the 'layperson'. Consequently, the course was changed to smaller, homogeneous target groups like school pupils, cardiac patients and environmentalists. After the paradigm shift in the late nineties and with the rise of constructivism and the idea of interactivity, the concept of the 'small public' became dominant, especially after Einsiedel et al. showed that nearly every scientific and technological dilemma creates its own public, often with a different composition. But probably more interesting than the size of the public is its new role. From the perspective of an increasing interaction between science and society, publics are acting more and more as stakeholders and experts by experience. The 'science and technology' public is no longer only a receiver of information, but also a participant in the communication process. Science and technology communication as an interface between science and society is broadened from a (top down) media-activity to an interactive activity, in which meaning is co-created. The participants are no longer representatives of an idea or group, but individuals with their own views, experiences and beliefs, who contribute to the creation of new ideas.