About federating between Discourse and Mastodon. There are a few things I don’t understand, I can’t, or/and I’m expecting too much. I’ve included some links. The content is in Finnish, but the content isn’t important, I guess.
Forum actors and boosting
If I’m understanding correctly, a category actor federates a topic by boosting it, because a real user is an actor, but things just don’t work that way, not yet anyway. So, is boosting the only way to achieve federation?
But it creates a situation where a Mastodon user sees it as a boosted item, and the original sender is, for example, my @Jagster@foorumi.katiska.eu. But they never follow the booster account, but the original one, like my personal forum account — but they can’t, because they see an approval request, and I can’t do that. So they never follow anyone.
Article vs. Note
I don’t understand what I should expect, but I think these are working in opposite ways.
If I’m using the Note form, Discourse will federate the first post as it is. Like this: Sokeriton kofeiini voi olla terveellistä - Ihminen, luonto & maailma - Katiskan foorumi (and as usual, ActivityPub links etc. are found as usual; by the way, I like that new way to show it, even if I don’t totally use it)
That one shows “Read more” but clicking it opens the content in Mastodon.
This one is an Article: Onko koiran peitsaaminen aina merkki ongelmasta? - Koiramaailma - Katiskan foorumi
It shows only the title and links to that topic. So reading in Mastodon is impossible.
edit: sorry about the mess after the edit, but I just realized this article type was shown coming from my forum actor, not as boosted by the category actor. It does it every time; two different things: original and boosting 
That was nice, though. But following my forum actor is still impossible because of approval; it acts like a locked account.
I tried to read this (mega)topic, and I bothered ask.discourse.com too. Is the ability to show the full article done exactly by linking, not by showing the content itself? If so, it’s unnecessary for Mastodon, because it can show longer content too, and I will use Note instead of Article.
Federation of discussion
When I’ve federated a topic, and someone is commenting there, that will show up under that topic just nicely. But if I comment on that topic in the forum, that will be federated, but no one sees it as a comment on that topic (or thread in Mastodon), because it has been sent as a boost by the category actor?
Is this a situation where the (official) Mastodon app says that maybe all comments aren’t on this instance, and you should open the original one — and no one ever does?
This is a topic where I had two independent discussions where the forum saw everything, but Mastodon didn’t know about comments written in the forum: Pikkulasten ruuat? - Retkeily & Melonta - Katiskan foorumi
Edit that topic is ~5 days old at the moment of writing this, and it has been boosted and published by the category actor, not by my forum user. Has something changed between then and now (yes, I do rebuild almost every day).
. Everything else is now clear, but that boost/writer thingy. I may not have any issue any more.
). And now used mastodon-app doesn’t update its content — but that is not your headache in any means.
) Discourse shouldn’t let me follow it in the first place (unless Discourse doesn’t know that in that moment). Anyway, it should not terminate following without telling me. Or did it… I haven’t check out logs, my bad.
).