vmm is an easy-to-use and configurable commandline tool for administrators and postmasters, used to manage domains, alias-domains, accounts, and relocated mail users. It allows fast and easy management of mail servers. It's designed for installations using Dovecot and Postfix with a PostgreSQL backend.
SpamCheck is an email scanning and quarantine system for Linux systems. Making use of a number of open source technologies, including SpamAssassin, Exim, and MySQL, it provides an easy-to-use, but powerful method to filter email for your domain. Once configured, multiple domains can be added and administered with the Web interface. Email is scanned and scored, non-spam is then passed on to a destination email server, while spam is either blocked or quarantined. Individual users can log in and review their quarantined email, and manage their settings through the Web-based interface.
Bulk Mac Mail is an an application for sending personalized mass email messages. It allows you to use message templates with multiple custom fields from the recipient database inside your messages. Customer lists can be imported from files of any type. Since all messages go through the standard Apple Mail's message delivery framework, they are absolutely indistinguishable from the messages that were actually sent by Apple Mail.
Mass Mailer for Mac is a high-performance bulk email program used to send personalized email messages using message templates to a large customer base from a single computer. It can import and export customer data from a wide variety of sources and handles multiple Web site mailing list subscriptions.
Kwaga BirdsEye is a desktop widget that recognizes email messages that matter and alerts the email recipient when the recipient receives an email that asks for something or requests a meeting, or when the recipient receives an email with a reply to an important email. The desktop application works whether or not the user has connected to email Inboxes. It supports Gmail and Google Apps, free.fr, and Yahoo mail accounts. Up to five accounts may be used. Kwaga BirdsEye automatically detects and prioritizes the people the recipient has already communicated with in the past (a.k.a. "trusted sources").