Whether agonistic or deliberative, it is evident that Europeanisation of national public spheres is hard to achieve by overlaps, synchronisation of news reporting, diffusion of Europeanist norms, or politicisation along single issues. The European Union’s common public sphere project may hence be in danger. This calls for explorations of other modes of public sphere for Europe. Are there traces of other modes of public sphere emerging in Europe than what the deliberative and agonistic theory lenses enable us to perceive? In this article, we suggest a model which is based on a cleavage theory of Europeanisation. With a point of departure in Rokkan’s cleavage theory (1970, 1975), we define the European public sphere as a composite architecture of communicative networks of ideological groups structured around Europe-wide political cleavages. We explore this mode of European public sphere by utilizing Facebook data and employing tools of social network analysis (Wasserman and Faust 1994).