@ArpComics The technical details are covered by @crepels in his series on Understanding ActivityPub <span>https://</span><span>seb.jambor.dev/posts/understan</span><span>ding-activitypub/</span></a”>1, but the gist is that a reply will only be relayed to OP if it’s a direct reply or OP is mentioned; otherwise a given toot (even if it’s a reply) will be sent to the author’s followers’ servers only.

(As I understand it; #activitypub experts are welcome to come correct me.)

activitypub
Understanding ActivityPub – Part 1: Protocol Fundamentals – Sebastian Jambor’s blog