I believe so, though I cannot find great examples to prove it. e.g. !memes@reddthat.com exists but is empty. Then again, I saw similar occurrences with my old instance, Discuss.Online, when nobody had yet joined !justpost@lemmy.world. So I joined it, waited a day or two, and then all the posts showed up - this is the way that communities used to have be federated, before Blaze went around to virtually every instance and joined almost literally every community to make it already happen for people:-). Anyway, Blaze seems to not have done that for PieFed yet, so I will do it myself.:-)

And dubvee.org if you’re from the glorious wild and wonderful state of West Virginia, America’s very second best Virginia (thus making it probably in the top 5 of all states in terms of my weird nationalistic appreciation of them)

It goes

1. The great and glorious Best Virginia
2. The Tar Heel State
3. Kentucky and its glorious bluegrass
4. The wild and wonderful Second Best Virginia
5. Ohio

(No but for real though nationalism is dumb)

No, I think it just blocks all lemmy.ml communities. Not posts/comments made by ml users on communities from other instances.

In my experience, it did greatly cut down on the tankie posts and comments I was reading because ml users’ political takes are mostly contained within their own instance. I only come across tankie takes once every few days now. And I’m on lemmy a lot.