For readers:
To be in control of the email lists you are added to on Substack, turn on email confirmations.
1. Log into your Substack account and click on your profile icon at the top right corner.
2. Select Settings in the dropdown menu.
3. Scroll to the bottom of the page to Security.
4. Select the toggle next to "Require verification to receive emails".
If you've already been added to a list without your permission, you can unsubscribe from the publication by following these steps.