The term "unsubscribed" refers to a status for contacts in your account.
How can Contacts unsubscribe?
Contacts can unsubscribe by clicking on the unsubscribe link in your mailings. The unsubscribe link contains identifier numbers for the account, mailing, and recipient and is automatically processed by our system to change the contact's status to unsubscribed, after which they cannot be included in any mailing from the account. Additionally, there is a List-Unsubscribe header included every email (it's not visible, but tells receiving systems where to send unsubscribes to be handled correctly.)
Any contact in unsubscribed status will no longer receive campaigns sent from your Delivra account. Future imports that include a Contact in the unsubscribed status will be skipped (no updates will be made to data, nor will the status change back to normal). To accommodate legitimate needs to return a Contact to the Normal status, we offer access to change status on the individual's record in the Contacts dashboard.