Every subscriber has a "type". This is the state of the subscriber: whether they're active, whether they've unsubscribed, whether they're on a trial, etc. We've added a few more types to make access and filtering easier:

• "churned" subscribers, which represent subscribers who were once paying for a premium newsletter and no longer are doing so. (You may want to reach out to them directly to get feedback or to offer them a discount!)
• "malformed" subscribers, which represent subscribers who have an email address that is not valid. Sometimes people mistype their email address or accidentally throw in a space or two.
• "complained" subscribers, which represent subscribers who have complained about your newsletter. You may want to reach out to them directly to apologize and ask them to give you another chance.
• "disposable" subscribers, which represent subscribers who subscribed from a disposable email address. These are often used by spammers to sign up for newsletters and then unsubscribe. (Buttondown will not send emails to these addresses so as to preserve your deliverability.)