@evan i think anyone who wants a “complete” view ought to stop expecting that for replies (short of recursively crawling the whole web) and instead work toward a distribution model where conversations exist in some context and are managed by the server responsible for that context. (see fep-7888 for a description of how context could work normatively, but tldr: send your Create to the context.attributedTo and they’ll distribute an Add which you can forward to your followers)
@trwnh I don't know what you're talking about. Every reply should include the original poster in their addressing, and the original poster's server should maintain the `replies` collection. Mastodon does this already. The `replies` collection should be an accurate record of the direct replies to a post.