Look at this photo of Hahn on his website. "Hah, it's a piece of cake," he seems to be saying. He was founder and CEO of Collabra Software, sold to Netscape. He was CTO of Netscape. He launched Lookout Software, a search application for Microsoft Outlook, which was snapped up by Microsoft barely more than a year ago. He played a role in shaping Good Technology's strategy. And he backed Zimbra, the Web 2.0 email service that has gotten quite a bit of buzz.

And now he is founder of Proofpoint, a Cupertino company that provides email services to companies that helps prevent spam, viruses and embarrasing correspondence that run afoul of securities regulations or internal corporate policies. Of course, his name at the company's Web site is above even the CEO's. Here's the news: Proofpoint has just raised $20 million more, adding to its $38 million previously. That's a lot of cash.

By the way, Proofpoint's latest round is the first investment by Bridgescale Partners, a private eqity firm launched by Rob Chaplinsky. We've written a lot about VCs who leave to start smaller early-stage firms. This is a case of a guy who goes the other way, later-stage.