Now that Microsoft offers Exchange as both a service and an on-premise product, it is beginning to align the features of the two offerings more closely, White said. When the company makes architectural decisions about the server product, it thinks about the service as well, she said. "We're thinking about them in a unified way."

It made it easy in Exchange 2010 to automatically configure access for certain employee roles, such as a compliance officer or human-resources manager, White said. "You can set it up [for people] to just have access to the mail boxes they need to search, and can turn that access on and off very quickly," she said.

In Exchange 2007, IT pros needed "an 80-page white paper" to do something similar, she said.