Here is what makes sense to me:
A notification is bound to an event and is made up an interval and a method.
If the method (SMS/email) or the interval (daily/instantly) varies we should get unique notifications regardless if they happen to be bound to the same event.
If the event, method, and interval are the same (regardless if the user happened to ask for both thread based and forum based notification for the same event -> a message posting) the user should only receive a single notification.
I do not want a UI for this. It would be great if the application decides (I just want the results to be intuitive).
