I realize the title question is a bit vague but I’m not sure how to make this question succinct… I had the thought when sorting by active posts and finding that the option doesn’t seem to work.

Basically I know from the past year a few things about how federation works (please correct any which are wrong, or have changed - this whole question may be obsolete for all I know).

1. The all feed is populated by instance users finding communities to join which populates them for the whole instance. (This is the reason I haven’t spun up my own instance)
2. Comments, posts, and other interactions from non-federated instances don’t show up, as though they don’t exist at all.
3. The all feed for each instance is unique as a result of 1+2.
4. The comments on each post could change based on instance.
5. The vote count on each comment can change based on instance. (Is this also the case for posts?)
6. Comments replying to a defederated-instance-user’s comment will also not show up.

But what about the sort ordering of those posts? If comments from non-federated instances don’t show up, do the votes or even the “engagement activity”? Could there be a post, say on beehaw, that I can see because we federate with them, which is wildly popular on an instance I can’t see, let’s say dbzer0, that looks to me like a mostly dead post way at the bottom looking sad and alone?

So in this hypothetical, post is on beehaw, and I can see it, but the top comments and upvotes are mostly from dbzer0 users, which I can’t see. How would the sorting work for that? I assume it would treat it as though dbzer0 doesn’t exist, but if all the top comments came from them, would that mean there’s just nothing there at all? Or is there some behind-the-scenes magic that counts the engagement from non-federated even if the activity itself is hidden?