At Piefed office hours, rimu@piefed.social and I got to talking about what's next for Piefed and the Threadiverse WG.
One of those things is moving stuff between communities (or in bbs parlance: moving topics between categories/forums).
Rimu suggested we use the already-existing as:Move activity, sent by the community (a group actor), with origin and target set, and with object being the post id itself.
I suggested we update this to use the resolvable context collection as object instead, which Piefed has supported since v1.2.
That should be enough to get a proof-of-concept implementation going between Piefed and NodeBB... a question remained as to whether this should be Announce(Move(Object)) or simply Move(Object).
Argument for former was that it was similar verbiage to other 1b12 actions.
Argument for the latter was that this is merely 1b12 adjacent and needn't follow prior art.
We'll likely put together an FEP for this.