the idea is to be able to turn on (or off) a notification option to be received by email, to notify us when a contact chose to unsubscribe from marketing emails.
For the moment, I have to create a If/so action in my workflows to be notified about this.
the important thing is to be able to modify those contacts as non-marketing contacts when they unsubscribe, they can do this now but it complicated to be notifed about this.