A turnkey open source messaging and collaboration platform.

Modular, extensible, notebook framework to make cross-platform interoperating prototype implementations. Allows shared input and display of sketches, text, equations, images, graphs, other data types. Tools for authentication, other services.

Groupware suite containing a base system and different modules including scheduler, email, file and projects. (PHP)

A planned PHP-based groupware including calendar, address book, forum, ticket system, WebMail, CRM and DMS.

Web-based open source groupware written in Java/JSP with support for PostgreSQL, Oracle and SQL Server.

A web-based Italian office communication suite for archiving digital documents. Works with Hylafax server.

A servlet implementation of an open protocol GroupWare product. Backend (search engines, news, weather, POP3/IMAP/LDAP/NNTP, database) is based on other open source packages.

Lucane is a free groupware platform written in Java, designed with extensibilty in mind.

Free Open Source Portal Server allowing point and click community, content and XML syndication management on the Web, email, cellphone, other media.

Moregroupware is a Web-based Groupware written in PHP4. Includes modules like calendar, notes, todo, and contacts. It is database abstracted and uses a template engine for output.

Topic Map based java system, "a testbed for developing tools for Web collaboration", Apache license.

onShore, a consulting firm, has a web-based, multi-user time-billing tool, GPL license.

OpenACS (Open Architecture Community System) is an advanced toolkit for building scalable, community-oriented web applications.