eLetters
The e-Letter system allows you to stay in touch with your customers by sending them rich content emails. All double opt-in functionality is automatically provided which allows you to concentrate on getting your message to your customers rather than worrying about if you've made any mistakes.
Using the e-Letter mailing lists you can target differnt emails to different subscriber types for example you can have a 'Customers' list which you can use to keep your customers up-to-date with your latest product and also have a 'Specials' lists where you can send out your latest product specials.