I looked at your About Zimbra web page. I have a problem with it.
You say, more or less, "We looked at what's out there and we think we can do better." That statement does not go far enough. In two or three years you will have the best collaboration software out there by far. Then what do you do?
Your mission is to make computer software that helps large groups of people accomplish complex tasks effectively. This includes sharing, archiving, synchronizing, and offline viewing of many different kinds of data.
That's my start on a more open ended reason for Zimbra to exist.
note: I'm posting this here because I can't find a better place to put it. Feel free to move it or route it to the appropriate people.