SMITIPS, that accusation is patently FALSE. Zimbra, which was owned by Yahoo, and is currently owned by VMware, is NOT harvesting emails. Not only is that silly, but you have absolutely no technical evidence to support such a strong statement.
Yes, the Zimbra Desktop software is not fantastic. However, this page is not for Zimbra Desktop, but Zimbra Collaboration Suite, the actual server, which I and many others have been using very successfully for years, and would never give up. It's simply fantastic.
Zimbra has a fantastic reputation in the industry. Not only does Yahoo continue to use Zimbra, but many universities, enterprises (i.e. comcast), and parts of US government use Zimbra. It has a very active open source community behind it as well.