ADJE WebMail is a set of Perl CGI scripts which provide a Web interface to existing email accounts on any POP3-compliant email server. The software provides a complete interface, including encoding/decoding attachments, email and URL markup in received emails, and an address book for each user.
CRM is a very powerful filtering and mutilation language based on regex operations. It is capable of classifying mail messages, syslogs, firewall logs, and other incoming streams of unbounded length. It has a very powerful sparse-spectral learning capability; given examples of multiple classes (say, business email, jokes, and spam), it can learn to discriminate the classes.
CRM114 is a Controllable Regex Mutilator and Smart Filter, designed for easy creation of filters for things like incoming email redirection, spam filtering, system logs, or monitoring processes. Filtering rules can be either hard-coded (such as regexes), soft-coded (calculated at runtime or read from an external file or process), or learned dynamically by phrase matching (as in Bayesian filtering, Markovian matching, Winnowing, or Hyperspatial classification). This makes it possible to create very accurate filters with very little actual work. Accuracies over 99.9% are achievable.
CRM114 is a generalized filter. It is useful for spam filtering, syslog monitoring, and other common tasks. CRM114 is a mutating filter based on regex matching, and it can call and be called by shell scripts and commands. When used as a spam filter, it can achieve over 99.9% accuracy.
Elm Millennium Edition is a text-based mail client. There are two branches: Elm 2.4ME+, which is based on Elm 2.4, and Elm ME+ 2.5, which also incorporates some code from Elm 2.5. Elm Millennium Edition contains enhanced MIME and character set support. A subset of UTF-8 (Unicode) is handled. It can read mail from a local mbox and POP and IMAP folders and can pass mail to the PGP or GPG programs. It can also view digests as a mailbox and reassemble fragmented (message/partial) messages. It includes modules for TLS/SSL, iconv, and SMTP.