CMC is a Perl/GTK+ mail client designed to be easy to use and fill the needs for features that are not present in other mailers, including HTML mail, multiple accounts, support for external viewers, compatibility with other mail clients, easy extendability, multiple mailboxes, etc.
ColdSync is a portable synchronization tool for Palm devices (PalmPilot, Handspring Visor, etc.) that runs under *BSD, Solaris, Digital Unix/Tru64, Linux, AIX, and Windows NT. It supports PalmOS 2.0 (original PalmPilot) and later. It is only known to support Visor syncing under FreeBSD and Linux, however. It supports IR syncing under Linux. ColdSync can back up, restore, install, and synchronize database, and can be extended and customized through the use of conduits. ColdSync is rather paranoid and takes pains not to delete anything it isn't 100% sure about.
The Collaborative Virtual Workspace (CVW) provides a "virtual building" environment where teams can communicate, collaborate, and share information regardless of their geographic location. CVW takes virtual meetings one step further and enables virtual co-location through persistent virtual rooms, each incorporating people, information, and tools appropriate to a task, operation, or service. The software optionally makes use of multicast tools to provide audio and video.
CommuniGate Pro is a high-end, industry strength Internet Mail server. It supports over 24 different operating systems including Linux/LinuxPPC,Solaris, MacOS X, FreeBSD, WindowsNT, BSDi, AIX, AS/400, HP/UX, Tru64, BeOS, IRIX, and S/390 for Linux. The CommuniGate Pro server takes full advantage of modern multi-threaded and multi-processor environments, and includes anti-spam protection, administration via the web, extensive multi-domain support, dial-up capabilities, cluster support, and unique IMAP multi-mailbox features. As a commercial product, it is distributed as keyware. The Free trial version is not time- or feature- limited.
The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, Webmail, and mailing list services within a single consistent framework. Individual components can be enabled or disabled at will. Courier implements basic Web-based calendaring and scheduling services integrated in the Webmail module.
Courier-IMAP is a lightweight server that provides IMAP access to maildir mailboxes. It supports folders, custom authentication modules, and virtual mailboxes. A compatible POP3 server is also provided. The source code is based on the IMAP module in the Courier Mail Server, but this build is independently repackaged to work with any other MTA that delivers to maildir format mailboxes.