This thesis explores if and how states can regain control over large social media platforms like Facebook, and by doing so ensuring that individuals on those platforms can de facto enjoy their human rights, as enshrined in international treaties. Today, the platforms are crucial facilitators of human rights but at the same time facilitators of threats towards the enjoyment of the same rights. Behind this duality hides three gaps, namely between individuals’ de jure enshrined human rights and their de facto possibilities to enjoy them on social media, states extensive de jure obligations to ensure those rights on social media and their limited de facto possibilities to actually do so, and lastly between the platforms limited de jure responsibilities to respect human rights and their extensive de facto influence over human rights. The reason that these gaps have arisen is essentially that public international law – mainly its strict horizontal character and its definition of jurisdiction as something exclusively tied to a delimited physical territory – is inadequate to tackle the virtual, cross-border, and non-state activity that the platforms are pursuing. To find what could be done to lessen these gaps, this thesis turns to theories in analytical jurisprudence and public international law: the identity of systems, legal pluralism and international legal subjectivity. The first suggests that this issue cannot be solved due to different legal systems having different identities and thus cannot be bridged. The second also suggests that the issue cannot be solved not because of differing identities of systems but because the platforms should be regarded as autonomous legal systems, not subordinate to state law. Finally, the third alternative suggests an actual solution: making the platforms subject directly to international law and universal jurisdiction. Even though this is a legally sound solution it is, however, not as simple a solution as it might appear.