At a time when online discourse is increasingly controlled by private platforms like X, previously Twitter, and Facebook, and when fake news risks affecting elections and public health in Europe and the United States, there is a growing need for more transparency in online discourse. The DIGIPOL project argues that misinformation is one attribute of a larger digital information ecosystem over which we urgently require oversight. The project aims to explore transparency in online discourse. The focus is not on a single information element, such as dis/misinformation, but rather the larger ‘digital information ecosystem’ within which online discourse occurs. In particular, the project aims to assess the central role of platforms in managing and directing this ecosystem. Platforms make user and content moderation decisions with little public oversight, but can also manipulate online spaces through randomized experiments, continuous updates, and nudging users. By building a theoretical framework on platform control, DIGIPOL provides stakeholders—including policymakers, researchers, and the public — with insights to better understand the influence of platforms over online speech and, ultimately, democracy.