Is it a function of the #ActivityPub spec or just the specific platform (mastodon, pleroma, etc) that when you click on a post it doesn't load all replies which forces you to click open in browser to see the full conversation?

finner@appdot.net The specific platform. ActivityPub defines a replies collection for every single post, which should include all replies. Mastodon, and others, ignore the replies collection, and just search for stuff that has been delivered that has the inReplyTo property set for the post. It’s a bad system.

@evan @finner https://www.w3.org/TR/activitypub/ says nothing about the `replies` collection, and even if it did, there is not currently a good way to follow a collection (or to do so recursively for such replies collections). The closest we have in-spec is inbox forwarding (which sadly doesn't get implemented by most fedi softwares!) but there's still the issue in maintaining a consistent and complete audience for who should get which notifications (and how to add or remove yourself to such audiences).