The emphasis on public participation in contemporary policy discourse has prompted the development of a wide range of forums within which dialogue takes place between citizens and officials. Often such initiatives are intended to contribute to objectives relating to social exclusion and democratic renewal. The question of 'who takes part' within such forums is, then, critical to an understanding of how far new types of forums can contribute to the delivery of such objectives. This article draws on early findings of research conducted as part of the ESRC Democracy and Participation Programme. It addresses three questions: 'How do public bodies define or constitute the public that they wish to engage in dialogue?'; 'What notions of representation of representativeness do participants and public officials bring to the idea of legitimate membership of such forums?'; and 'How do deliberative forums contribute to, or help ameliorate, processes of social inclusion and exclusion?'.