Digital platforms underpin transnational markets for goods, services, labour, and ideas. By promoting cooperation, regulating conduct, and combating opportunism, some platforms have grown larger in trade value than national economies. But the platforms’ rules and mechanisms are not necessarily fair. And in recent years they have begun extracting a growing share of the value for themselves. Academics and policy makers have started to ask how these new institutions could be better held accountable. In this talk I will draw on my recent book Cloud Empires: How Digital Platforms Are Overtaking the State and How We Can Regain Control to discuss difficulties with the two dominant approaches, antitrust and regulation. Much of the difficulty stems from the fact that our polities are organized along territorial lines, even as platforms’ memberships and transactions are transnational. Using case studies from major platforms, I will discuss the prospects of members constituting themselves as a transnational polity and demanding direct accountability from platforms’ rule-makers.