How does Pooki's Mahi obtain email addresses?

Pooki's Mahi never purchase email lists.  Pooki's Mahi's corporate policy is very strict about acquiring email addresses. 

1. Customers either signed up for the newsletter or was added by a partner.
2. Customers can unsubscribe any time.
3. Pooki's Mahi will never a customer's email address to a newsletter group. Customers need to add their email address themselves.