When I purchase something online, I get a flurry of emails:

1. Welcome!
2. Confirm your email address!
3. Thank you for your order!
4. Your order is about to ship!
5. Your order has shipped!
6. Your order was delivered!
7. How was your order?!
8. Here’s what other customers are buying!
9. New product!
10. Amazing offer!
11. We miss you!
12. Our privacy policy has changed!
13. We miss you!
14. You earned points from your last order!
15. Your points are waiting for you!
16. Are you sure you want to unsubscribe?!?
17. Sorry to see you go! Please allow 2 weeks to process your request
18. Our privacy policy has changed!
19. Your balance is $0!
20. Refer your friends!

It's a good thing the carbon cost of an email is negligible.