Electronic mailing list servers may be set to forward messages to subscribers of a particular mailing list either individually as they are received by the list server, or in digest form in which all messages received on a particular day by the list server are combined into one email that is sent once per day to subscribers. Some mailing lists allow individual subscribers to decide how they prefer to receive messages from the list server (individual or digest).
Win-back: An existing customer is soon approaching the end of his yearly subscription. The customer hasn’t used your product in 3 months and you need a way to win them back and keep them for another year. Create a “win back” email that sends an automated email to all customers that are coming to end of their contract with a list of new product features and a short plan on expected releases in the next six months.