What is opt-in vs opt-out?
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Opt-in means the subscriber had to actively sign up. They took a deliberate action to say yes. No email goes out until they explicitly asked for it. Opt-out flips that assumption: you can email them by default, and they have to take action to stop receiving from you.
Under GDPR, opt-in is required for marketing to EU residents. Under CAN-SPAM (US), opt-out is technically permitted. You can email someone without prior consent as long as you include a functioning unsubscribe link they can use within 10 business days.
In practice, opt-out lists are a trap. Mailbox providers like Gmail and Outlook evaluate engagement signals to decide inbox placement. People who never asked to receive your emails don't engage with them. Low engagement means the spam folder, regardless of whether the emails were technically legal to send.
The legal minimum and the deliverability minimum aren't the same standard. Opt-out might be legally permitted in your jurisdiction. It still undermines your ability to reach anyone. If you want to understand what makes consent strong enough to hold up, read about explicit vs implicit consent.
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