tl;dr — how do PieFed/Lemmy/Mbin handle cross-posting?
Currently, when a NodeBB admin moves a topic from the uncategorized pseudo-category into a local category, we federate out an as:Announce, people typically think of that as a "boost" or "share".
That worked fine when the entirety of the category list was your local categories plus the "uncategorized" pseudo-category. However, now that NodeBB is moving towards supporting remote categories (via group actors), this UX makes less sense. We wouldn't want to "move" a topic out of the category it is supposed to be in, just for visibility to other local users. Additionally, topic moving was limited to administrators, and from the get-go we knew it would eventually cause issues because people other than admins would want to share topics to other local users.
This is where the "cross-post" functionality comes in, which is entirely new to NodeBB. I don't think this is new to other AP-enabled threaded discussion software. The idea would be that if a new topic comes in, whether it's uncategorized or not, any user could "cross-post" that topic to a local category, where it would be visible to other users on that instance. On the ActivityPub side, we would then federate out an as:Announce as we already do.
Is this what PieFed/Lemmy/Mbin already do, if they support cross-posting? What other alternative solutions would there be to this problem?
cc @rimu@mastodon.nzoss.nz @andrew_s@piefed.social @nutomic@lemmy.ml @bentigorlich@wehavecookies.social