How Does Mastodon Work?

I tried GNU Social a long time ago, but it was mostly technical people talking about technical stuff. Great if that's what you're into, but it's no basis for a general use social network. Niche networks are fine, but I don't get the impression that's what early federated social media proponents wanted.

Email does show us a greater need in Mastodon to emphasize trust-relationships over ill-defined "social groups" as better ways to form relationships. In the early days of email, the ISP was an easily formed trust relationship, and in today's arena a lot of people have preferred trust relationships to hosts like Google (Gmail) or Microsoft (Hotmail/Outlook), etc. The "people interested in Topic X" that most of the instance lists are focused on doesn't give you any information towards trust relationships, and is possibly in the way of forming them.

The immediate problem is that those large companies like Google or Microsoft with lots established trust relationships aren't expected to play in Mastodon/ActivityPub, so you need to bootstrap new ones. Luckily, there's a lot of room for trying to bootstrap new trust relationships. Some instances have already been playing with ownership models, and companies are easy enough to form if people want to place those ownership models into transparently accountable units/liability-protected units that are recognized by larger governing bodies than just themselves.

A friend I follow, Darius (@darius@tinysubversions.com), has also been ruminating on this quirk in Mastodon adoption lately and trying to find ways to establish trust relationships with instances, though so far his solution is to stick to a smaller scope and start with the idea of "you trust me, so let me host your instance" among friends. That idea might scale if there were enough folks like Darius doing that, and I've sent very simple invites to possibly add friends to my instance that I control, and have been looking to come up with governance documents based on that idea, but haven't yet had anyone take me up on that invite, so I keep procrastinating it.

From the other direction is tougher, because you have a many-to-many relationship to try to consider. It's a variation of the problems of OG OpenID and/or Mozilla Persona (RIP to both). If I want to use example.account@gmail.com, how do you map that to a "main" instance if you can't ask gmail.com because Google doesn't currently care about WebFinger or ActivityPub? Do you use a central database somewhere? Does that defeat the goals of decentralization you were going for in the first place?

If it's the former, then I don't understand the problem you're describing. Why can't trust simply be a hierarchy from the Mastodon devs-- who you have to trust anyway-- down to a small, diverse set of the largest and most performant instances (as defined by those devs themselves)? That would cover the vast majority of users and still obviously leave room for anyone who wants to run their own instance.

Even if the vast majority of users/devs think it's unethical to have a hierarchy/centralization, as you point out there isn't any known alternative at present. So the only practical alternative is to punt, which inhibits adoption and hardens the implicit social group hierarchies which you point out are problematic.