Developing a theory for the remote audiences of digital networks, we dialogue with social psychology and social theory to describe a novel form of communication that is delivered to everyone and no one at the same time. This is the invisible audience. At the same time as people express themselves to a generalized, invisible audience over social media, the ‘everyone’ of this invisible audience is often narrowed in a very specific way: echo chamber effects. The invisible audience and echo chamber effects both reinforce a solipsistic horizon for every person, and these individual horizons come partially together under echo chamber effects, constituting a multiplicity of separate ‘homophilic assemblages’ characterized by normative and political alignment, one-dimensional communication, and black-and-white thinking. We call this a ‘splitting public sphere’. On the whole, rational debate is curtailed, under the reign of soundbites, memes, and angry venting. The lack of exposure to reasoned disagreement makes people more susceptible to authoritarian rhetoric and propaganda.