There's an undocumented attribute of the
media_metadatathat would facilitate us implementing this feature (provided it still exists, as the
r/redditdevcomment was made about a year ago)
In slack, when a thread is created off a message, that message expands into a sort of preview that shows the last few messages within the thread. The best part about this is that this message "bumps" down when there are new posts in it. That is, if posts in the thread are the latest message in the overall channel, the conversation preview message is the latest message in the parent channel.
Implement a feature that mimics this somewhat through the use of notifications in the parent channel when there are new posts in a thread. Allow this to be enabled per channel, with a default of it being disabled for the guild. Only post a notification every interval. The minimum amount of time between activity in the thread that must pass to trigger a notification ought to be 6-8 hours.