Exogenous constitutionalisation? Platforms’ content moderation policies as global proxies

Platforms are increasingly becoming a vehicle for extraterritorial regulation. Most prominently, doctrines about the binding effect of fundamental rights, that is, the state action doctrine in the US and the European horizontal effect doctrine. Such doctrines have become particularly relevant in the context of content moderation as a reaction to the substantial influence of platforms over user-generated content. Platforms may, until now, mostly rely on the US intermediary liability framework and invoke case law at their advantage when it comes to free speech issues. In Germany, the horizontal effect doctrine has a long-standing tradition and is being revived to justify the platforms’ responsibility regarding their users’ freedom of expression. This happens through policies, regardless of whether court decisions are supposed to have a binding precedent effect. When platforms implement decisions about the restrictability of free speech, they become proxies of constitutional doctrines.