Confirmed Opt-In (sometimes called Verified Opt-In) is a process used to ensure that only people who want to receive your information are subscribed to your list.
Here's how it works:
A confirmation message is sent to the subscriber. This message contains a link automatically included in a customized message that the subscriber must click on in order to confirm they want to receive your information at the address provided to you
After clicking on the link, the subscriber becomes active on your list and will receive your messages
If the subscriber does not click on the link in the confirmation message, they will not become active on your list.