What are the rules for sending confirmation messages?
Contacts who opt-in to your Express Email Marketing® mailing list through your website receive a confirmation message at the email address they provide through the subscription link. Contacts must confirm their intent of joining your mailing list. You cannot manually send confirmation messages through Express Email Marketing to potential Contacts; they must use the opt-in link on your website.
Contacts that you import into your database (individually or through a list) do not receive confirmation messages.
Confirmation emails do not count against the monthly email quota.