On the Völkerrechtsblog, Amélie Pia Heldt writes about hate speech and the responsibility of platforms like Facebook or Twitter.
Hate speech: circumscribing, understanding and fighting hate speech - still a current topic in the context of online communication. [...] it affects all global communication services and all legal systems, albeit in different ways. However, the handling of hate speech and the countermeasures have had little effect so far. A promising approach would be to deal with the responsibility of platforms without necessarily equating them with state actors.
You can read the entire article here.
Heldt, A. P. (2019): “Ein globaler ‘Dauerbrenner’ – Der Umgang mit Hate Speech auf Online-Plattformen [A Global 'Long Runner' - Dealing with Hate Speech on Online Platforms]”. In: Völkerrechtsblog. https://voelkerrechtsblog.org/ein-globaler-dauerbrenner/ (last access 02.12.2019).