The new customers, which include Carnegie Mellon University and Princeton University, are at different stages of deploying , which is free and includes e-mail, calendar, office applications, IM, video conferencing, IT controls and other components. Thirteen are implementing it broadly for students, faculty and staff university-wide, .

Companies, schools and government agencies are becoming increasingly comfortable turning off e-mail and collaboration servers in house and shifting instead to cloud systems hosted in vendor data centers.

Not only does the cloud model reduce maintenance and hardware costs, but it also simplifies workplace collaboration, because the software is typically designed for sharing and joint editing of documents.

Microsoft leads the on-premises enterprise email and collaboration market, but is having to fight tooth-and-nail to defend its turf as customers switch to the cloud-based model.

Not surprisingly, the biggest fight in this market is between Google Apps and Microsoft's Office 365, which includes online versions of Office, SharePoint, Lync and Exchange.