Sphere transgressions: reflecting on the risks of Big Tech expansionism.

The rapid expansion of Big Tech companies into various societal domains (e.g., health, education, and agriculture) over the past decade has led to increasing concerns among governments, regulators, scholars, and civil society. While existing theoretical frameworks-often revolving around privacy and data protection, or market and platform power-have shed light on important aspects of Big Tech expansionism, there are other risks that these frameworks cannot fully capture. In response, this editorial proposes an alternative theoretical framework based on the notion of sphere transgressions, which draws on political philosopher Michael Walzer's theory of justice. The editorial not only introduces the sphere transgressions framework, but it also highlights its potential to generate novel research questions. Furthermore, this editorial introduces eight articles and one commentary from a group of interdisciplinary scholars that critically examine Big Tech expansionism by reflecting on this expansionism from the perspective of different societal spheres or by engaging with the sphere transgressions framework itself.