We are working on our CAN-SPAM compliance, and have our Unsubscribe wording the way we want it. Our app mainly sends e-mail when it is notifying users of various work-related events. If a user unsubscribes, their email is added to a blacklist, so notifications are generated for them, and then not sent to unsubscribed/blacklisted addresses.
How would you word reversing an unsubscribe action? We have considered "opt in", "opt back in", "resubscribe", and "subscribe". The Opt In options are inconsistent with the Unsubscribe wording, but is accurate to what's happening. Resubscribe and Subscribe are consistent with Unsubscribe wording, but is not really what's happening, since the address is being removed from a blacklist, and the unsubscribe action is being reversed.