Zimbra Collaboration Suite (ZCS) is an email and calendar server plus much more. In addition to email and calendar, it provides document storage and editing, instant messaging, and simplified administrative controls all in an award winning webmail user interface built with the latest AJAX web technology. ZCS also provides mobility and syncs to desktop client applications; the server is deployed on commodity Linux and Mac server hardware.
The Zimbra team uses an open source software development methodology. That means they use many proven and highly web-scalable open source components as building blocks in Zimbra Collaboration Suite and Zimbra Desktop.
The key to Zimbra’s success is the vast community of over 20,000 developers and IT professionals who help make the product better by providing feedback, support, and code contributions. They are active in the Zimbra Forums and Wiki, with about half using Zimbra Collaboration Suite (ZCS) Open Source Edition (available for free) and half using ZCS Network Edition. The community is a great place for getting Zimbra tips; you can easily find free expert help for all our products there.