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?
Yes, I would assume that defederated instances would just have to be ignored. I hadn’t thought of this. Good point.