Kartik Prabhu
“if (3) had come 3 days after (2), wouldn’t it make sense to show (3) in Kyle’s stream? ”
Broken links so I don’t really know what (1), (2) and (3) are, but this is still possible to do with webmentions. It is just a matter of sending the webmention notification.
“only the other hand, if Kyle and Kartik went back-and-forth 10 times in a single day on that thread, would you want all of Kyle’s responses to appear in his stream? ”
*would you want* is a very good question. IMO multi-threaded forum-esque displays are a nightmare from UI/UX perspective.
“and what if there are other people involved? If Alice responds to Kartik, will Kyle ever see it? And what if Bob responds to Alice? ”
This is left as a choice to the two communicating members. In principle, I could send a webmention to Kyle every time my post gets a reply from a third person and he could choose to update his thread with the same.
In all excellent points raised, mainly about these being reader experience problems to be sorted out.