Zimbra: 4 Million Paid Mailboxes and Counting

What do Digg, Mozilla, the University of Bern Switzerland and the Times of India have in common? According to an announcement today, they are all among the 1000+ customers of web based open source communication and collaboration suite Zimbra.

Founded in 2003 in San Mateo, California the company today announced that it has passed four million paid hosted and on-site mailboxes. That’s a small but growing and very significant number compared to the 150 million plus seats sold by Microsoft Exchange. Zimbra took $16 million in funding from Benchmark Partners, Redpoint Ventures and Accel Capital.

We’ve profiled the moves toward a web based office by Google, Zoho, Microsoft and countless small startups. Zimbra includes a long list of features that other companies are just beginning to offer. Microsoft says that Exchange Server 2007 is due out at the end of this year or early next year; if it does in fact become available as a final release in that time frame it will be interesting to see if it can do what Zimbra can do.

The webmail client looks and acts a lot like GMail but supports email, calendar and contacts from Outlook.
There’s RSS feed reading, Salesforce integration, mobile access without download of a separate client (no Windows mobile support though apparently), tagging, document and spreadsheet sharing and collaboration and Ajax embeding of rich documents inside one another. Zimbra has explicit support for mashups and the kinds of voice integration that Microsoft products require third party tools to perform.

It’s an impressive offering that’s obviously growing in adoption. If you’re looking for evidence supporting the viability of Web 2.0 in the enterprise, Zimbra’s customer announcement today makes for quality fodder.