Board Thread:News and Announcements/@comment-28083312-20200813185835/@comment-28083312-20200813212746

You can follow threads, just as you can follow Forum threads now. You can display only particular Discussions categories, just as currently you can display only particular Boards, in order to search for specific posts. You can also tag posts, which acts the same way as Forum Topics work (& indeed Topics will convert into tags). Search is also on the horizon, which not even Forum has, but likely not for a good long time.

I'm unsure what you mean by sub-threads. If you're referring to something like Slack's ability to have a thread within a conversation, thread within a thread, then no that is not possible, but neither is that currently possible in Forum right now.