BoltMail
One-Click Unsubscription
If you want to grow your mailing list, then there's 2 things that you absolutely must have: a double opt-in process, and a quick way to unsubscribe. In some countries, it's actually mandatory by law that every email has an unsubscribe link in it. The unsubscribe link should take the recipient directly to a page where they are then removed -- courteously -- from your mailing list.