When a subscriber on your list declines to receive further communications, it's called an unsubscribe. CAN-SPAM and other anti-spam laws require services like turboSMTP to have an unsubscribe process in place.
We require that you include an unsubscribe link in your email templates.
We strongly encourage you to use our double opt-in process for list subscriptions. Accounts that use double opt-in methods tend to experience fewer issues than those who collect through single opt-in.