Two-screen viewing is becoming a regular activity as citizens watching television share their thoughts online in real time about the programme they are watching, particularly during political and media events. This chapter surveys research to date to identify what difference this makes to the quality of political debate, to political behaviour and democratic engagement, and ultimately to questions of power and hierarchy. We explore methodological innovations in academia and the social analytics industry. Two-screen viewing is part of a hybrid media environment that parties, media organizations and electoral regulators must adapt to. While two-screen viewing in principle allows citizens to publish their views in public to an unprecedented extent, we suggest that these larger organizations are quick to find ways to integrate two-screen behaviour to strengthen existing political and media hierarchies and sustain existing digital divides. We conclude by suggesting that attention to these continuities is as important as attention to novelty and change.