@benroyce @bitsnpieces @mastodonmigration @mekkaokereke
Agreed on all counts. On top of that, block-and-move-on doesn't even work, because setting up a new account costs no money and almost no effort. Evil dude harasses you, you block him, he sets up twenty more sock puppet accounts and does it all over again.
I'm still trying to think of ways to solve that that wouldn't inconvenience people of good will. I'm thinking along the lines that an account wouldn't be able to @ someone, except in a public reply, until it had enough reputation. It would gain reputation by posting publicly, by reaching a certain age, by getting favourites and boosts from reputable accounts, and by reporting other people's posts that mods decided were evil. An account would lose reputation by being blocked or muted by reputable accounts or by having any admin action taken against it.
One idea that would work, but which I've rejected because of its impact on benign users and because of bureaucratic overhead, is to make each new user pay a small (maybe £5) deposit when setting up a new account. The deposit would be refunded after a month unless the moderators had closed the account because of abuse.
I don't know. This all needs more thought.