I thought it would be good if making a post with a URL alerted me if the same URL has already been posted to another community/ server. Then it could offer to make the body of my post a comment under that post instead.
What do you think, and do any technical people familiar with Lemmy / Piefed / ActivityPub know if suc h a feature is possible without huge overheads?
Defederation of various forms would appear to make this a difficult thing to do.
There was a situation the other day where a post was called out for being a repost, but it was entirely possible that the OP couldn’t see the original because their instance (let’s say “A”) had defederated the instance (“B”) where the original poster was based. And all this was (or at least could have been) in a group on a different instance entirely (“C”).
I won’t say this makes it impossible, but it’s clearly non-trivial.
Yes, I would assume that defederated instances would just have to be ignored. I hadn’t thought of this. Good point.