[dsr_]

Suppose that everyone who participated ran their own server, population 1.

Then choosing to block other servers would be equivalent to blocking other people, which we agree is a good thing.

Now someone comes up with an adblock list: subscribe to it, and these servers will not bother you. It's probably not perfect, but it improves your experience a lot. If you don't like it, switch to another, or don't subscribe to any.

And now we are back where we started: you can choose to either subscribe to a policy (join an existing server) or be independent.

[luckylion]

Is it public which servers an instance is blocking / what servers they are federating with?

[ekidd]

Normally, yes. Different kinds of blocks are listed at the bottom of an instance's "About" page. Often there's a note for each blocked instance, too, though some admins leave that blank.

I've seen a couple of servers which only show the block list to users with accounts. These tend to be restricted-membership servers, ones which don't publish their member directory or local feed, either.

[berkes]

Most servers even have an API endpoint for this.