Hello, John.
I didn't get the relation of the BP's changes and notifications about such changes and marketing campaigns. What do you mean? Could you please clarify your requirements?
About notification of the change of the BP. I'd suggest to try the following. The business object BP (BUS1006) has the event BusinessPartner.Changed. You can assign a workflow which will be triggered on such event. And this workflow should implement the logic to send the notification.