Dada Mail can help you manage a mailing list, offers complete support for safe, closed-loop opt-in subscriptions, sends out mass mailings, keeps an archive of your messages, and allows you to share your messages in many ways. It runs on your Web hosting account and you interact with it through your Web browser, making it available anywhere you have a connection to the Internet. You do not have to rely on a third-party list management system with costly monthly fees. It is rich with features, but tries to keep it simple. It is designed to favor flexibility, extensibility, and ease-of-use over core speed or extremely flashy but hard-to-use features. It is designed to be installed, set up, and understood by regular people who have Web sites, but has enough advanced features to entice more proficient users. If you've ever installed a bulletin board or blog software, you should be able to install Dada Mail without too many problems. Dada Mail can scale. You can install Dada Mail on most any basic hosting account and start sending out messages. If your mailing list grows large, you can switch to sending with a more powerful third-party system, like Amazon SES, where there's potentially no limit on the number of emails you may send, all without having to change mailing list management systems or your hosting.
The SeaMonkey project is a community effort to develop an all-in-one Internet application suite. It contains an Internet browser, email and newsgroup client with an included Web feed reader, HTML editor, IRC chat, and Web development tools, and is sure to appeal to advanced users, Web developers, and corporate users. It uses much of the Mozilla source code powering such successful siblings as Firefox, Thunderbird, Camino, Sunbird, and Miro.
Fetchmail is a free, full-featured, robust, well-documented remote-mail retrieval and forwarding utility intended to be used over on-demand TCP/IP links (such as SLIP or PPP connections). It supports every remote-mail protocol now in use on the Internet: POP2, POP3, RPOP, APOP, KPOP, all flavors of IMAP, and ESMTP ETRN, ODMR, SMTP, LMTP, and local delivery agents.
Clam AntiVirus is an anti-virus toolkit designed especially for email scanning on mail gateways. It provides a number of utilities, including a flexible and scalable multi-threaded daemon, a commandline scanner, and a tool for automatic database updates. The core of the package is an anti-virus engine available as a shared library.