Notification is the core concept of Business Notification. Broadly speaking, a notification consists of:
Some business logic in Navision
A "document" that Navision sends to Business Notification
Some business logic in Business Notification
An e-mail message
The Navision business logic: the starting point for notification is the Navision business logic (the program code that makes Navision work). A Navision developer creates a test that will send a "document" to Business Notification when some predefined condition is fulfilled. This is called "raising an event." An example would be a test of whether the total amount of a sales orders is above a certain figure. If it is, the event is raised.
A "document" is sent to Business Notification: When the event is raised, Navision automatically sends a "document" to Business Notification. This "document" contains information about the event, as well as data that the Navision developer has decided is useful to have access to in Business Notification.
Business logic in Business Notification: when Business Notification receives a document from Navision, it will use its own, internal business logic to see if a notification e-mail should be sent, and to whom it should be sent. This business logic, or "rules," are setup in the Business Notification Designer.
The conclusion is that a notification e-mail message is sent when:
The Navision business logic raises an event.
Business Notification has a (started) scheme that responds to this event.
For this specific event, and with the data in this actual instance, a notification has been set up to be sent.
And there is at least one internal user subscribed to the scheme, or at least one external recipient has been set up.
It is true, though, that once the system is running, and from the viewpoint of the end-user, the actual e-mail message can, in many ways, be seen as the notification itself, and will often simply be referred to as such.