A brief overview of Mercury 

Mercury is a mail server - an application that acts as a post office for a group of users, receiving and sending mail, and managing their mailboxes for them. In service since 1993, Mercury is a proven performer, with a huge range of features and some of the best filtering capabilities in the e-mail world. Highlights of the program's feature set include -

• Protocols: Mercury has support for all the widely-used Internet mail standards in existence, including POP3, SMTP, IMAP, PH, and SSL.
  
  
• Filtering: With rule-based content filtering, general-purpose filtering, system content management policies and Lukas Gebauer's powerful SpamHalter Bayesian spam filter built in, Mercury's filtering capabilities allow you total control and automation of your mail.
  
  
• Mailing lists: Mercury features a full-fledged mailing list manager that can handle mailing lists with tens, thousands or even tens of thousands of users. Incredibly rich and configurable, and offering web-based subscription management for users, Mercury's list management features are amongst the most powerful in the industry.
  
  
• Extensible: Mercury is heavily programmable, and numerous plugins are available for it.
  
  
• Easy installation: You don't have to be a twenty-year veteran administrator to install Mercury - its installer will do most of the work for you, leaving you to explore and tweak to your heart's content later.
  
  
• Ultra-configurable: Just about everything in Mercury is configurable, so even if a particular feature doesn't quite work the way you want by default, you can usually adjust it to do so.
  
  
• Fast and Robust: Mercury can move huge quantities of mail quickly and reliably, with little overhead. Sites are using single Mercury servers to service thousands of mailboxes, running on old systems that couldn't even be used as desktop PCs any more. Mercury is hugely stable, secure, and reliable, running for weeks or months on end without needing attention.

... And this is just the tip of the proverbial iceberg. Please click here to view a more complete feature list, or even better, download it and try it out: it is free for non-commercial use, and commercial users are welcome to try it for 60 days before deciding whether or not to buy.