If you go here you'll see all your subscriptions: http://nikonites.com/subscription.php?do=viewsubscription&folderid=all
You can check the ones you don't want to receive email notifications for and batch update them at the bottom.
Got it -- not at all obvious. Didn't there used to be a simple click box to unsubscribe from a thread? This mode need better labeling.
If you go into an individual thread, under thread tools there is an option to subscribe/unsubscribe. Is that what you mean? This is how it's always been though. I agree that it could be more visible.