@drq @mittorn @skobkin
It's like trying to make toaster-refrigerator hybrid. Platforms made for entirely different goals.

Old-school forums were literally made to discuss topics, not "blog" about life or something else. "Offtopic" was chastised, so things won't turn into a mess. Yet you could quote one or two users by using "quote" and it linked a user by straight up mentioning them.
If some thread turns into another type of discussoin which is not necessarily offtopic, users either agree to create a separate topic, or they just keep it in, since it is probably meaningful to the thread in general.

Comments on posts in twitter, fedi, heck even news and imageboards while being used like a chat look like a mess anyway and rely on links and visuals to be followed more or less easily.

Chats like discord/matrix, it is easy to see in chat UI/UX when you've been added to a group chat or have specific discussion started.

Here, in fedi, not much exists for merging separate threads into one by different people, because it wasn't made for chatting specifically, and it's only natural for threads to diverge eventually.