Express Email Marketing™
Tour - Send Confirmations Screen Shot
Opt-In Confirmation Required

One of the default confirmation request messages must be sent to all subscribers that are added or imported to the mailing list. Select subscribers with a Confirmation Required status on the View Subscribers page, and then select Send Confirmation from the Apply this Action dropdown list to go to the Send Confirmations page. Customers who do not respond to the confirmation request will remain in a Confirmation Pending status and will not receive mailings.