@julian @kirkmoodey Mastodon is currently working on a spec for their groups implementation. Maybe get everybody together to hash out a common spec, including those who already have a group implementation like Friendica/Hubzilla, Misskey/IceShrimp/Sharkey, Pleroma/Akkoma?

IMO The simplest way would be to garnish a bit of extra data onto the normal FEP 1b12 process.

Create a new post (Create -> Page to the instance that hosts the community, which in turn does Announce -> Create -> Page to followers) and add an extra field to the Page which is the URL of the original post. That will establish the association.

To reject the cross-post, return HTTP 400 (403?) to the POST to the inbox on the initial Create -> Page ? Or send a Reject activity, either way is fine but the 400 seems easiest. Lemmy returns 400 for a lot of things so we have some prior art in that direction.

Mastodon is currently working on a spec for their groups implementation.

Any links to this and/or discussion of how it relates to other FEPs?

Duplicating the object would mean the discussion is split between objects. The ideal implementation would be the same object present in multiple categories/communities. Is there desire for this in the threadiverse?

If the link goes to a controversial news article and it's get posted into pro- and against- community/group the comments will spiral out of control and it won't be a pleasant place.

Maybe it could be implemented as a toggle per group/instance within one fedi software. It shouldn't be in Activity Pub protocol.

THanks ... turns out I knew about that: the implementation for the NLNet grant, but never released. My impression is that it's been on hold since then, and there's so much other discussions of group-releated FEPs that I certainly hope they'll incorporate newer thinking if and when it moves forward.

I haven't looked into the differences between their implementation and how groups are implemented using 1b12, but what I have discovered is that the 1b12 community is much larger than I gave it credit for.

How would this work on the NodeBB side? Multiple categories associated with one topic?

projectmoon@forum.agnos.is basically, yes. It would be a little too involved to upend the entire system to support multiple cids per topic — a lot of our existing code relies on cid being a single value.

This would be an add-on logic of sorts, where each topic has a canonical category, but can also be cross-posted to other communities/categories.