This book is the result of Ana's doctoral thesis, which was conducted at the Perelman Centre of the Université libre de Bruxelles (ULB), and updated in her current position at the Center for IT & IP Law (CiTiP) of the KU Leuven. Her research was initially funded by CAPES to whom I am very grateful for providing me with the opportunity to work with Ana. Multiple twists and turns marked this successful doctoral research which began with a complete lockdown of Brussels, following the November 2015 terrorist attacks in Paris, and ended with several confi nements and drastic curfews imposed on the civil population in an attempt to contain the Covid-19 pandemic.

It was in this turbulent political and social context that Ana tackled a major challenge, which, at that point, had been overlooked by the legal academic writing in Europe: Mapping how discrimination against protected classes (including gender, ethnic origin, age and sexual orientation) on online platforms were developing, in particular through the design of these platforms. In a judicious way, Ana correlates real occurrences of discrimination against protected classes to three design aspects of online platforms: (1) their aesthetic choices concerning users’ protected markers, (2) the design of matching tools that enables users to exclude others with protected aspects from receiving goods, services and work offers, and (3) the design of evaluation systems that facilitates the permanent exclusion of users of protected classes from the system.

At the time of her research, the issue of discrimination against protected classes in online platforms, due to their design, had mainly attracted the attention of scholars in United States business schools, despite the fact that the transition of entire economic sectors to online platforms had already created several challenges for the respect of fundamental rights and, more particularly, for the principle of equality and non-discrimination in the European Union. To fi ll this gap, this research covers both European Union law and the federal law of the United States. This comparison with the United States is essential to draw lessons from litigation that did not yet exist in Europe. Moreover, the comparative approach is essential for a better understanding of the windows of opportunity offered by the sources of convergence and divergence of nondiscrimination laws, the liability regime of Internet Service Providers, and the data protection legal framework, in both legal systems.