Platform Duty of Care after the Supreme Court Ruling on the Marco Civil da Internet

This paper offers a systematic survey of the Brazilian legal scholarship to examine how the duty of care has evolved across different legal fields and to illuminate how these developments can inform current debates on platform regulation and the enforcement of the Brazilian Supreme (STF) Court ruling on intermediary liability. The analysis of the duty of care across various areas of Brazilian law reveals its central role as a principle and often the basis for liability. Essentially, the duty of care imposes a diligent, attentive, and preventive conduct, aiming to avoid damages (as obligations of means), but also serves as the basis for the obligation not to cause harm (as obligations of result). When the duty of care is expressed by an obligation of means, what is required from the agent is the adoption of specific conduct: the application of their best efforts, knowledge, and techniques to achieve a desired goal, without, however, guaranteeing the final outcome. By contrast, where the duty crystallizes as an obligation of result, the legal focus is on the non-occurrence of a specified harm: responsibility is triggered by the materialization of the adverse outcome, independently of the actor’s intent or the efforts undertaken. The STF as the Court recognized a preventive duty of care and identified a series of procedural obligations for digital platforms, yet it did so within a framework that allows those preventive duties to generate liability when serious harm occurs. As Brazilian doctrine already integrates preventive and compensatory logics, it becomes clear the hybrid nature of the STF’s decision and situates it within a broader legal tradition.