Cross-posts are entirely new and separate posts from their originals.

@rimu@piefed.social excellent... yes this is the kind of difference I'd love to explore and potentially put together an FEP for...

Hmm... considering that Piefed cross-posts are entirely separate posts, then if the original is edited, then the modification is not carried over to the cross-posted post, correct?

I'm thinking that for NodeBB we could continue to have cross-posts reference the canonical topic. They'd simply be part of a separate audience as well.

Whether this is local-only or not, I am not sure yet. Perhaps for federation purposes we'd still report the original category (if there is one) under audience

Yes the modification is not carried over and the cross-post will often have a different author from the original too. While creating the cross-post the cross-poster could have edited the title and description, too. The only connection is that they have the same url (in the attachment). Lemmy adds the text "cross-posted from link-to-original" to the beginning of the body content but it's just text, not an attribute on the Activity.

Room for improvement!

Also moving what NodeBB calls a topic (a post in Lemmy/PieFed) from what NodeBB calls a category (community in Lemmy/PieFed) into a different category (without spawning a new topic or leaving the old copy behind) is much needed but not implemented in Lemmy/PieFed/Mbin.

@julian@community.nodebb.org On Mbin we don't have a button so the user can cross post it to another magazine/community/group. What we count as "crossposts" are just posts linking the same URL (and sometimes title matching, though I don't like that part). But like Rimu said these are entirely different entities with different apIds often from different instances

Based on the replies received, it does sound like at present that if cross-posting is a consideration, it is something done locally, and not something that is explicitly declared when federating outward or retrieved via AP.

There are also multiple definitions of cross-posting:

1. Multiple, disparate topics sharing the same attachment url (PieFed)
2. Author targeting multiple audiences
3. Non-author sharing object to additional audiences

One of those is really not like the other, which does complicate things somewhat. Thankfully, it does seem like that the way PieFed handles it, is local to the instance.

A good first step might be to narrow down the definition of cross-posting—at least from a protocol level—to a combination of the latter two:

> "A user (which may or may not be the object author) sharing an object to additional audiences"

Of course, this also happens to be what I'm looking for: the association of an as:announce activity with an as:target pointing to an as:Group actor.

Would this be of interest to anybody here? The fallback mechanism is to just treat the announce as usual.

>the association of an as:announce activity with an as:target pointing to an as:Group actor.

I was thinking about adding target on Announce to bring FEP-1b12 and Conversation Containers closer to each other (in CC we have Add with target).

Can't Group simply be in to of Announce?

@silverpill @julian i was going to say that yes, to/cc/audience are more specific versions of target, specifically audience targeting. not sure Announce.target is needed here... what would be ideal is if multiple Announces existed, one for each category. an AP Announce represents a "share" and not necessarily a "reshare", so it's not like one of them has to be the "original"; they can all exist at the same tier.

@trwnh@mastodon.social sure, makes sense. That to/cc already exist in the wild as arrays means one less thing to worry about with multiple cross posts.