It isn't enough to include unsubscribe instructions in the message body copy, as CAN-SPAM requires U.S. e-mail marketers to do for messages that are all or mostly commercial. Marketers must make the unsubscribe process as trustworthy as possible so subscribers will feel they can use it with confidence and not have to resort to the "spam" button in desperation.

If recipients don't trust you as an e-mail sender, they'll be more likely to report you as a spammer to their ISP. If the ISPs get enough complaints, they'll either block your e-mail or route it to the bulk folder instead of the inbox. That damages your reputation and hurts your ability to get e-mail delivered correctly.

Lack of trust in the unsubscribe process can ultimately hurt e-mail deliverability.

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