So what would a better system look like?

It would start by ranking platforms according to their level of social risk. At the lower end would be modest online spaces like community forums, hobbyist groups and fansites. These should be subject only to minimal regulation, and remain largely immune from liability for the content they host. This is not because small platforms are always pleasant places – many are dens of iniquity – but rather because they are easy to leave and easy to replace, and the harms they generate do not usually spill over into wider society. Added to which, too much regulation could be stifling. At the other end of the scale would be very large, important platforms like Facebook and Twitter. These have the capacity to frame the political agenda, rapidly disseminate content and shape the opinions and behavior of millions of people. They are difficult for users to leave, and for rivals to challenge. They are vital spaces for civic and commercial life. These kinds of platforms need more robust oversight.

Of course, size would not be the only guide to risks—small platforms can pose real social risks if they become hotbeds of extremism, for example–but it would be an important one. The Digital Services Act, adopted by the European Parliament in July, plans to distinguish between “micro or small enterprises” and “very large online platforms” that pose “systemic” risks.

Next, platforms categorised as sufficiently risky should be regulated at the system or design level (as proposed for the UK’s Online Safety Bill, which is currently on ice). Lawmakers might, for example, decide that platforms should have reasonable or proportionate systems in place to reduce the risk of online harassment.