The production of expert-to-layperson documents in private and public companies is an area of research that is gradually gaining ground in research communities throughout the world. This article discusses the nature of public communication written by experts or semiexperts and aimed at a large and heterogeneous audience, often potentially the entire population of a country. The article analyzes common barriers to this kind of communication, and considers topics such as the implications of very broad target groups, expert-to-layperson communication and the legislative introduction of mandatory genres as opposed to genres which have evolved naturally over time. The case of the patient package insert is outlined as a prototypical example of ‘public communication’ suffering from the problems brought about by the existence of these common barriers.