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, PieFed just blindly accepts everything.

Yep, I’ll document it in some way. A FEP seems overkill as it’s really just adding a bit more data onto Actors and Activities, not a big deal.

Each community in PieFed can have it’s own set of “flair” options that posters can attach to their posts. Clicking on a flair will filter the community to only show posts with that flair so they function as a filtering mechanism as well as a visual identifier.

Community moderators can manage the flair that are available in their communities:

When creating posts, expand the ‘more options’ area to assign one or more flair to your post:

See it in action at https://piefed.social/c/piefed_meta

Flair doesn’t federate yet but it will in coming days.