Mad Mimi Email Marketing
Mad Mimi is a lovely, simple email service that lets you create, send, share, and track emails. Over 100,000 businesses use Mad Mimi to do email the simple way.
This extension allows you to automatically add your customers to your Mad Mimi mailing lists when they purchase your products. You can add them to individual lists for each product as well as your general subscribers list.
If you are using the Mailer API inside Mad Mimi then you can also send your new customers welcome emails when they sign up.
The extension also comes with a shortcode that you can use to give your customers full control over the mailing lists to which they are subscribed.