Germany’s most important philosopher of democracy and democratic discourses is unhappy. In his latest book, Jürgen Habermas argues that “half-publics” are taking the place of public spaces and that democratic discourse is challenged by heated online debates. But the character of the debates itself is not the central issue. The bigger challenge is making sure that the private rules and practices of platforms that shape online debates are aligned with public values. A number of platforms and NGOs have started to develop deliberative approaches to platform rules. But designing digital democracy is challenging.