I wasn't exactly sure where this should be posted, so if this needs to be moved then please do so.
In the Zimbra Trademark and Branding FAQ, it has the following:
Can I use "Zimbra" or a Zimbra product name in one of my website URLs?
No. You may not use Zimbra or any other proper name associated with the Zimbra offering in a URL or domain. For instance 'www.zimbrahosting.com' is not allowed.
In searching for some Zimbra information this evening I stumbled upon the following site:
Host Zimbra - the open source alternative to Microsoft Exchange
Seems like this would be a violation of the trademark unless this is "sponsored" by Zimbra? However, with the site design I would find that interesting...