Zimbra Founder Satish Dharmaraj to Depart Yahoo

Satish Dharmaraj–the founder of open-source email start-up Zimbra, which has been at the heart of significant new changes to Yahoo’s key communications services–will be leaving the company.

The move, to be announced internally later today, is not a big surprise, even though Yahoo paid $350 million for Zimbra in the fall of 2007.

Dharmaraj (pictured here) had previously stepped back from day-to-day leadership at the Yahoo communications and communities division, which is run by former Zimbra President and CTO Scott Dietzen.

But the departure of an innovative entrepreneur like Dharmaraj–although typical when big companies buy start-ups–is never a good thing, given that it’s more important than ever to keep innovative leaders at Yahoo.

New CEO Carol Bartz will have to tap internal leadership if she hopes to turn Yahoo (YHOO) into the kind of fresh opportunity she said it could be when she was hired earlier this month.

Yahoo introduced new email services recently, based on some of Zimbra’s technologies and concepts.

That has been important, since Yahoo Mail has always been a company bright spot and has remained the bigger provider of Web email to general consumers.

But most agree that Yahoo has allowed the Google (GOOG) mail offering, Gmail, to suck up all the oxygen in the room with more flashy features like threading of conversations while not serving up a strong response quickly enough in an arena Yahoo pioneered.

Zimbra vaulted its effort at differentiation from the hyped Google offering forward more quickly.

More importantly, it has strengthened Yahoo’s ability to make online email act more like a computer program than a Web page, which has been the main focus of late of Yahoo, Google, Time Warner (TWX) online unit AOL and Windows Live Hotmail from Microsoft (MSFT).

In addition, since Zimbra was designed with flexible and open Ajax programming tools, it made it easy for third-party developers to make many other applications that jack innovation from the outside, making the communications platform the center of the Web experience with video, search and other tools.

It’s not clear where Dharmaraj is going, but here is a video interview I did with him last year after Yahoo bought Zimbra: