Abstract: On 17 February 2024, the Digital Services Act (DSA) became fully applicable in Europe. The DSA takes a novel regulatory approach to intermediaries by imposing not only liability rules for the (user) content they host and moderate, but also separate due diligence obligations for the provider’s own role and conduct in the design and functioning of their services. This new approach fundamentally reshapes the regulation and liability of platforms in Europe, and promises to have a significant impact in other jurisdictions, like the US, where there are persistent calls for legislative interventions to reign in the power of Big Tech. This short book brings together a group of renowned European and American scholars to conduct an academic transatlantic dialogue on the potential benefits and risks of the EU’s new approach. It is the final version of an online symposium first published in the Verfassungsblog in early 2024. The contributions to this book can be divided into two larger themes. After a general introduction to the topic (João Pedro Quintais), a first set of contributions considers transversal issues of platform regulation in the EU and US, namely those of consistency (Rebecca Tushnet), due process (Eric Goldman and Sebastian Felix Schwemer), fundamental rights (Christophe Geiger and Giancarlo Frosio; Martin Senftleben) and the potential “Brussels Effect” of the DSA (Martin Husovec and Jennifer Urban). A second set of contributions zooms in on key regimes, critically assessing rules on trusted flaggers (Eleonora Rosati), human in the loop (Rachel Griffin and Erik Stalman), access to data for researchers (Niva Elkin-Koren), and transparency (Pamela Samuelson and Natali Helberger).