Service e-mails: Think of confirmation e-mails after you have signed up for a newsletter or the e-mail that your order is on its way. Newsletter mails: Periodic mails at a fixed moment, for which the subscriber has specifically opted in. Event-based e-mails: This is also called marketing automation. Emails are not sent at a fixed moment, but based on behavior and events. An autoresponder containing the downloaded e-book, a birthday mail sent to the recipient on the right day or an automatic appointment reminder.