Something which notifies you whenever a new comment or reply is made to a selected post/comment, so that you can keep track of any new conversation.

Something like this would be awesome as a core Lemmy feature IMO. It would essentially turn a post (or maybe any comment tree?) into a matrix style room. Lemmy is actually decent for long term discussion (e.g. helping someone with a problem), but not if there are more than two people involved.

That’s not really the same thing because ‘alt.tv’ doesn’t aggregate everything under it. Let alone the other relationships they describe (e.g. biochemistry).