RoboPostman is an e-mail communication tool for Mac that lets you create and send custom messages to predefined lists of recipients. By using this program, you have access to various typing and background image settings. You also get an easy way to manage your address book and keep your mailing list clean.
The Attachment mode provides you with configurations that prove to be of great use when sending e-mails to large lists of recipients. You can include all attachments on every sent message or let the program randomly select one file per e-mail. The program has an additional tool that immediately removes all broken files from the attachments list.
The only issue I have with this application is that it might take a while to configure e-mail deliverance settings from the Preferences and Deliver menus (you need to log in to your e-mail account using a browser, find and copy the necessary connection details). Once you complete these steps and enter the proper SMTP and POP3 details, you can start sending the customized e-mails to your recipients.
Briefly, RoboPostman is a program that replaces the need to open the browser each time you require to send an e-mail. Its price is affordable and my belief is that it can increase your productivity at the office when it comes to sending customized e-mails to entire lists of recipients.