Using the pre-defined audiences, schedule campaigns against each set.
This would create workflow wherein basis the subscription age, a user gets different sets of notifications.
This workflow can be further optimized by incorporating the different activities that a subscriber might/might not do on a website. For an e-commerce store, those activities would be - viewed a product page, added items to cart, transacted successfully, etc.
Based on this the new audience can be created such as:
- Subscribed 1 day ago but did not add items to cart
- Subscribed 7 days ago but did not add items to cart
This would create a drip campaign that focuses only on those users who subscribed 1 day and 7 days back but hadn't added any items to their carts yet.