The literature on polarisation has seen a proliferation of possible types of polarisation in recent years: from conventional forms of ideological and issue-based polarisation through affective and identity-based polarisation to interpretive and interactional polarisation, and beyond. It remains unclear how these may be systematically identified and distinguished by comparative empirical work, especially if such work is also going to take into account national and regional specificities. We present a conceptual framework of a large-scale research project that explores the drivers and dynamics of partisanship and polarisation in online public debate. We approach this challenge by identifying four major domains: polarisation in news coverage; polarisation amongst news audiences; polarisation in online public discourse; and polarisation in the underlying structure of online networks. Further, it is important to note that not all polarisation is inherently problematic. We therefore also ask at what point polarisation turns from benign to destructive.