To be fair, Lync Online today provides instant messaging, video conferencing and other collaboration features. But Kelly says Lync in the cloud isn't as sophisticated as Exchange in the cloud, which has been offered for several years.

"Exchange is the most mature, Lync is next," Kelly says. "I'd say is the least mature."

While Office 365 does let customers access SharePoint servers hosted in Microsoft's cloud data centers, the ability to customize SharePoint Online will be limited compared to SharePoint servers that customers manage themselves.

Moving Office 365 out of beta

The Office 365 beta ended this week, with Microsoft moving beta customers to production code. While Kelly says tweaks were made to improve availability and the user interface, not all of the problems noticed by customers during the beta have been solved.