How to unsubscribe from topics

presuming you mean broad topics like Messages

navigate to the topic on the forums website

look at the top right for the [ Follow/Unfollow ] button.

click your preference.

done.

edit: clarified what I meant to say after MrHoffman's different take on 'topic'

Usually:

Sometimes, not so much. Some threads can be inexplicably sticky.

Forums can be subscribed too, and Apple has a pile of notification-related settings in the ASC preferences available behind the round icon in the upper right of this and most other ASC webpages (when logged in).

I mean questions I've asked where other folks are adding their own problems at the bottom, then getting into debates with other users, and I'm being copied in on discussions that no longer relate to me or my resolved question.

So I thought, if I unsubscribe they can keep there conversation going without filling my inbox with it..

But as far as I can see, there's no way to disconnect from the original question. I've tried the bell icon but that just confirms you're subscribed, it doesn't unsubscribe unfortunately.