The aim of the lecture is to reflect on the interaction between two long-term changes in contemporary societies: the changes of political culture in democracies on the one hand, and the change of communication infrastructures on the other, resulting in hybrid media systems including social networks. The changes have implications for the nature of public spheres as opportunity structure for democratic speech and institutions. I suggest to introduce the notion of dissonance, disconnection and noise in public spheres in order to describe the multilayered, synchronous and disparate processes of communication in hybrid media systems. The interaction of the noisy public spheres and the hollowing out of democratic political culture yields unintended consequences: The dynamics create a new disinformation order and push new political actors to the fore. The conditions threaten established patterns of authoritative information flows and public debate which put contemporary democracy under serious stress.