Have you ever tried to follow anyone from an instance that your instance refused to federate with? I am wondering how big of a problem this is. Not that I have encountered it, mostly just see this as potential a drawback of Mastodon's approach to federation.

Good question! I hadn't tried, but just found a random user on an instance that mine doesn't federate with and clicked Follow. It took me through the remote follow and that user did appear on my list and showed up in searches when they didn't before.

Unfortunately I seem to have chosen an abandoned or dormant account for my test, so I can't say for certain whether posts will show up in Home, but I would expect so given the other visibility changes. Hopefully someone else with some fedi experience can chime in.

Given how discovery in Mastodon works, by following "boosted" (think: re-tweeted) content creator or reading new people in a discussion, you wouldn't even know these accounts exist - sure, you can manually enter a mastodon id in the search bar to go directly to an account somewhere else (and thus try to access a potentially blocked node), but that's not the common use-case.

Now, if that increases or decreases the problem space is a philosophical question. I personally do have issues with blocking instances as a whole because one admin disagrees with another admin on unrelated issues.

If I get denied access to other people to organise around, e.g. building our own zen retreat because my admin and their admin disagree on political factions or because one admin nuked the connection to another instance for not being trigger-happy enough against their own users, everyone loses. Such technical possibilities and - in fact - recommendations run against the ideas of a civil society.

I see the situation you described in the last paragraph as a very real possibility. Not going to defend Twitter, but at least it can’t ban whole organized communities at once. Mastodon’s federation that is left up to instance admins to decide on is bad design.

I would prefer to use an instance that has no control over who I can follow. As an added benefit, this instance wouldn’t have to fully federate with every instance I follow users from, so wouldn’t add all updates to the federated feed.

This way the instance would only be responsible for user identities but would not have much control over who its users can follow. I still don’t fully understand why Mastodon did not choose this design.