I have changed my mind about anonymity online, and I want to set out why, because I argued the other side for years. The case I used to make was straightforward. Anonymity protects the vulnerable — whistleblowers, people in hostile countries, anyone whose opinion could cost them a job. Real-name policies were introduced by companies with a commercial interest in identity, and they were sold with a safety argument that the evidence never really supported. All of that is still true and I have not stopped believing any of it. What changed is that I stopped treating anonymity as one thing. There is anonymity from the state, anonymity from your employer, anonymity from other users, and anonymity from the platform itself. These are four different properties. A system can give you the first three and none of the fourth, and for almost everyone that combination is what they actually want. The mistake I was making was arguing about a slider when the real question was who each end of it protects you from. Once I separated them, most of the disagreements I had been having turned out to be people defending different columns of the same table.