In recent years, the explosive growth of the digital economy and the dominance of technology giants have brought serious challenges. Core platform services operated by global tech companies such as Google, Apple, Facebook and Amazon have many features that open up opportunities for abuse. In response to these processes, the European Union adopted the Digital Markets Regulation (DMA), which aims to promote fair competition and manage market dominance in the digital sphere. At the heart of its provisions are obligations for gatekeepers, i.e. organizations with significant influence on digital markets. Accordingly, the study presents the DMA‘s responsibility issues for gatekeepers.

The rapid rise of decentralized online social networks (DOSNs) introduces a transformative shift in digital communication, moving away from centralized systems and leveraging blockchain technology to ensure user autonomy, data transparency, and resistance to censorship. While these platforms promise significant advantages, such as enhanced privacy, reduced operational costs, and increased interoperability, they also present critical legal and ethical challenges. This study explores these challenges through a multidisciplinary approach, integrating legal analysis, case studies, and theoretical frameworks. Key issues include the tension between immutability and content moderation, the complexities of jurisdiction, and the implications of blockchain splits for accountability and governance. The analysis highlights the need for hybrid solutions that combine decentralized architecture with external oversight, including stricter regulation of hard forks and designated regulatory responsibilities. The findings provide a roadmap for balancing innovation with user protection, aiming to foster sustainable, ethical development of DOSNs while addressing their inherent risks.

This paper explores the growing regulatory role of very large online platforms (VLOPs) through the lens of digital constitutionalism. It argues that while these platforms operate under private legal frameworks, their governance functions—especially content moderation and algorithmic decision-making—closely resemble public regulatory authority. As platforms increasingly shape the terms of civic participation, public discourse, and access to information, a normative gap has emerged between the private character of their power and its public consequences. The study identifies three core questions: what motivates platform self-regulation, whether platforms exercise public-like functions, and whether digital constitutionalism provides a viable framework for constraining their power. Drawing primarily on a comprehensive literature review, the analysis confirms that platform self-regulation is strategically motivated, that platforms exercise quasi-public authority, and that digital constitutionalism offers a promising—though still evolving—response. The findings suggest that constitutional values such as transparency, due process, and the protection of fundamental rights must increasingly be applied to powerful private actors in the digital environment to uphold rule-of-law standards and democratic legitimacy.