AP has a tool for that called inbox forwarding and mastodon uses it for sharing the comments under posts. It works like this: you send a reply to a user with their follower collection as the recipient. You of course cannot know who is following that user, however they than just forward this reply to the follower collection, because the server knows that it has authority over that collection. https://www.w3.org/TR/activitypub/#inbox-forwarding
I am part of the mbin team and I am really tired of hearing shittalking about us without any reason. Nobody has any reason to call us anything but passionate.
When melroy started the fork, really weird accusations were thrown around without being based on anything…