Citadel is an advanced messaging and collaboration system for groupware and BBS applications. Users can connect to Citadel using any telnet, WWW, or client software. Among the features supported are public and private message bases (rooms), electronic mail, real-time chat, paging, shared calendaring, address books, mailing lists, and more. Unlike other collaboration servers, Citadel provides its own data stores and is therefore extremely easy to install; you don't have to "bring your own" email and database because they're built in. The server is multithreaded and scalable. In addition, SMTP, IMAP, and POP3 servers are built-in for easy connection to Internet mail. Citadel is both robust and mature; it has been in production since 1987.
NullLogic Groupware is a modular Web-based groupware and email system designed for contact management and event scheduling. Additional features include private messaging, public discussion forums, webmail, shared bookmarks, file sharing, call tracking, order processing, an XML-RPC API, and integrated POP3 and SMTP servers.
Blue Smiley Organizer is a Web-based script to manage your bookmarks, diary, reminders, to-do lists, contacts, knowledge, and file upload in a multi-user environment. It also includes its own live support help system, blogs, RSS feeds, customizable themes, and a discussion forum. It can also used as an AdSense ready application.
Vanilla is a WikiClone written in REBOL. It is useful for collaboratively working on projects, tracking todo items, managing adresses, and creating Web logs. All page editing takes place in the browser. Vanilla features a simple templating system, a full-featured user and session management system, and an extension architecture for writing simple Web applications in REBOL.
The Gordano Messaging Suite (GMS) is a highly flexible and reliable suite of messaging products. Customers can choose which components meet their needs from email, Webmail, collaboration, instant messaging, calendaring, SMS, and list server software all of which can be complimented by high level anti-spam, anti-virus, and archiving options.
Zadolbator is a simple reminder component for Jabber server. As it is installed on the server side, it can be used by all users of this Jabber server, and does not depend on the client software used. Its main purpose is to remind you about events such as birthdays or holidays, though it can be used also for keeping your everyday reminders about meetings, things to do, etc. It uses the iCalendar format to store events, so some basic understanding of iCalendar is needed to use it. This also simplifies importing existing events if they're in iCalendar format.