If you'd like to allow your email recipients to unsubscribe from your emails, you can use Unsubscribe Links.
To use Unsubscribe Links, create a campaign. In the MergeMail pane on the right, click on
Advanced, then enable the
Add Unsubscribe Link check box.
When this is enabled, MergeMail will add a small unsubscribe link at the bottom of your campaign. If a recipient clicks on it, they'll see a simple page that lets them unsubscribe from future emails. If they unsubscribe, then any emails you try to send to them in future campaigns will not be sent. On the campaign page for future campaigns, you'll see that they've unsubscribed.