How does this format work?
A user subscribes to receive Push Notification from a Publisher's website. Once a user is subscribed, they will receive a push notification ad that consists of an icon, creative, title, and a short description. By tapping on a notification, a user is redirected to your advertising campaign’s landing page/target URL. By the way, it is easy to control your subscription: a user can unsubscribe at any moment via their browser settings.
Might be interesting:
How to create a Push Notification campaign?