The Brazilian Supreme Court (STF) has been grappling with the issue of horizontal effectiveness of fundamental rights in the context of digital platforms. This concept refers to the application of constitutional rights to private relationships, including those between users and digital platforms. The STF has been examining the extent to which digital platforms, such as social media companies, can exclude users or remove content without violating their fundamental rights.
The court’s deliberations on this issue have been influenced by its previous rulings, including the RE 201.819/RJ and ADI 4815/DF cases. In the former, the STF recognized that fundamental rights can be violated in private relationships, while in the latter, it held that the protection of freedom of expression and information is not limited to state action, but also extends to private actions.
The debate over horizontal effectiveness of fundamental rights has gained momentum in recent years, particularly with the rise of digital platforms. The STF has been called upon to examine the responsibilities of these platforms in protecting users’ rights, including the right to freedom of expression and information. The court’s decisions have significant implications for the regulation of digital platforms and the protection of users’ rights in Brazil.
The STF’s examination of this issue is not limited to the Brazilian context. The court has been drawing on international experiences and comparative law to inform its decisions. For example, the German Federal Constitutional Court has ruled that social media platforms can be considered “public forums” and that users have a right to freedom of expression on these platforms. Similarly, the Italian Court of Rome granted a precautionary measure to restore the accounts of CasaPound on Facebook and Instagram, emphasizing the need for proportionality in content moderation.
Digital Platforms Regulation
In Brazil, the STF has been dealing with cases related to the exclusion of users from digital platforms and the removal of content.
It requires a detailed understanding of the relationship between private entities, such as digital platforms, and the state. The STF’s decisions on this issue will need to balance the need to protect users’ rights with the need to respect the autonomy of private entities. As the STF continues to grapple with this issue, it is likely that we will see further developments and refinements in the court’s approach to regulating digital platforms and protecting users’ rights.
In cases such as RE 1.037.396/SP and RE 1.057.258/MG, the STF examined the regime of civil liability of application providers and declared the partial unconstitutionality of article 19 of the Marco Civil da Internet.
Content Moderation Challenges
Minister Luiz Fux emphasized that the state’s regulatory framework for digital platforms is insufficient and that the STF declared the partial unconstitutionality of Article 19 of the Marco Civil da Internet to address these gaps. The STF has also been examining the issue of content moderation on digital platforms, considering whether procedural guarantees (such as prior explanation, contradiction, and the right to appeal) are provided.
The Sentence T-256 of 2025 from the Colombian Constitutional Court qualified social networks as “public forums of a sui generis nature”, as they blur the rigid distinction between public and private. The Court emphasized that the State has duties of regulation and supervision of content moderation in protection of users, but must not impede the capacity of these companies to “define rules and moderate content” in their services.
