Small companies may opt for a cloud-only Office 365 implementation, but midsize and large businesses are likely to pursue hybrid deployments for now, analysts say. That's partly because on-premise software provides functionality not yet available in cloud-based versions.

Cornerstone Mortgage Company is pursuing this hybrid approach. Rather than upgrade its on-premise Exchange server, Cornerstone is deploying Office 365 to about 900 employees throughout the United States. The company is using SharePoint Online and the suite's videoconferencing, IM and Web meeting capabilities, while maintaining custom applications in-house.

CIO Christopher Meyers expects to save 40 percent on infrastructure costs for communication and collaboration over five years. But he's not rushing to move more on-premise software to the cloud.

Meyers would like Microsoft to draft a strategy for financial companies using Office 365, to ensure that the product always complies with government regulations. "We'd like to make sure we get something that works for us long term," Meyers says.