Zimbra has the most advanced Web Interface with maximum number of features including Calendaring, Document Management, Task Management, Address Book and many more…
The Administrator and End User Web Interface of Zimbra is AJAX-based with rich and interactive user functions (access via HTTP or HTTPS). The interface automatically updates to display messages and other functional updates.
Zimbra also provides Themes option to user which enables customization of colors and appearance of the web. Another interesting feature of Zimbra is Rebranding which enables the user to use custom logos in the web interface to make it more attractive and standardized. Zimbra provides the ability to display ads which are based on the content of the subject and the message fragment by using Keyword based ad serving. Banner ads can be added or placed in Zimbra Web Client.