Priority of subscription
For instance, you work with a bookstore site. Some users only want to receive notifications about changes in the status of their orders. Others want to be notified about upcoming promotions and sales. And there are others who regularly read your blog, where you share information about the hot news in the world of literature. To limit communication within one topic, three resources are created: Transactional Notices, Promotions and Blog. The customer can choose which resources to subscribe to and what newsletters to receive.
As a default, new subscriptions always get a higher priority. In other words, the contact information that the user provided the last time they subscribed becomes the primary contact information. This is the email or telephone number to which messages will be sent in further newsletters.
Sometimes subscriptions to the same resource and to the same channel get the identical priority. In such cases, the campaign sends only one message anyway. The address is randomly chosen.