[dredmorbius]

There have been such blocklists circulating for some time on other platforms, notably Twitter. Those could become problematic where they were adopted without review, and/or those who were listed lashed out all the harder against those they thought had promulgated the lists.

I became aware of this when use of the lists and/or the drama that accompanied them leaked into the Fediverse a few years ago.

The Fediverse also effectively works in ways as a "subscribe to moderation policies" network, in that each individual instance has its own moderation policy and blocklist (individuals and instances), which is probably closer to what you've described than any of the other examples I've noted. This ... has some benefits and frustrations as well, particularly as swapping mods isn't as frictionless as your ideal version would be. There's also the "broken threads" dynamic, similar in ways to that seen on G+, though with the Fediverse (a closer analogue to Twitter) there's no top post, and no original-author-as-moderator dynamic, which means that if a particular thread is interrupted by a blocked profile/instance, the thread as a whole tends to fragment. Devs are aware of this and may be looking at other ways of aggregating threads, e.g., by having multiple "refers-to" type headers (see the Mutt email agent's threading model for more on this).