MAILreader - Listen to e-mails instead of reading them.

MailSite SE - Communicate with other mail servers on the Internet.

MailTrain Express - Send mass e-mail with ease.

Mailtraq - Meet your proxy, mail, and news server needs with one package.

Mass eMailer - Start mass e-mail campaign without using your ISP mail servers.

Maxx PDFMailer Professional - Send e-mails from any application.

MDaemon - Incorporate a full range of mail server functionality.

MDaemon GroupWare - Share Calendar, Task, Contact, Notes, and Journal folders with other Outlook users.

Message Parse - Extract and sort data from incoming e-mail messages.

Monsoon Mass Mailer - Send out multiple e-mail messages at a time.