Zimbra’s entry into the groupware/messaging market is the most interesting in that they really rethought the architecture and design of a groupware product. Zimbra is positioned as messaging and collaboration 2.0 with its mashup platform (via Zimlets which allow the product to share and sync data with third-party data sources and service providers) and its slick AJAX-powered webmail and offline client. On top of this, they still offer standard messaging and collaboration features, along with many high-end, enterprise-grade features (only available in their commercial product) such as LDAP and AD support, high availability, archiving, support for Outlook sync and mobile devices, and many others.

Like Scalix, the company was recently bought by Yahoo and is now offered as a hosted instance (although news reports indicate that Yahoo may be selling Zimbra soon), commercial turn-key product or a community-supported downloadable product.

Like Zarafa, integration with other open source products exist like SugarCRM, Alfresco, Asterisk (IP-based PBX) and XMPP (instant messaging). Like Open-Xchange and Scalix, definitely should be on the short list for any midsized to large company looking at deploying a collaboration platform. Its extensibility and rich UI make it a good choice for companies looking for a platform to integrate with form-based and workflow applications making it my choice for companies wishing to look for an alternative to Lotus Domino. A solid offering.