Zimbra is an open source server and client technology for next-generation messaging and collaboration. Zimbra delivers innovation for both the administrator and the end-user as well as compatibility with existing infrastructure and applications (both open source and proprietary).
Zimbra is open source server and client software for messaging and collaboration - email, group calendaring, contacts, and web document management and authoring. The Zimbra server is available for Linux, Mac OS X, appliances, and virtualization platforms. The Zimbra Web 2.0 Ajax client runs on Firefox, Safari, and IE, and features easy integration / mash-ups of web portals, business applications, and VoIP using web services.
Wikia offers free MediaWiki hosting for your community to build a free content wiki-based website. Find out why you should use Wikia and request a new wiki in any language or see our list of wikis to visit an existing one.
A site where you can have a secure, optionally private, ad-free wiki of your very own for a few dollars a month, or an insecure, ad-infested, public wiki for free. Neat-O.
Wookie is a project that creates open specifications and open source software for adding widgets to your applications. [able to do real-time updates too]
Foswiki is a wiki, so you and your team members can collaborate and edit pages directly in the web browser. For advanced collaboration, Foswiki lets you enter macros (similar to Excel) to automate pages and build entire applications from within your browser.