As a major unified communications player, Microsoft is still evolving. The vendor's telephony, messaging and collaboration tools are extensive yet immature.

Microsoft's Office 365, the most widely used enterprise cloud application, boasts a bevy of UC tools, including Skype for Business, Yammer, Groups, SharePoint and OneDrive. The commercial version of Office 365 has more than 70 million monthly active users, according to Microsoft's latest earnings report in April. That number has jumped by 20 million users in the past year.

Despite its success, Office 365 still has some work to do, especially as it relates to unified communications, telephony and a cohesive messaging strategy.

For starters, Office 365 telephony, in the form of Skype for Business, is not yet a full telephony replacement for what enterprises have on premises, according to J. Peter Bruzzese, an Office 365 MVP and CIO of ClipTraining, an end-user training website.

Skype for Business on premises simply has more capabilities than Skype for Business in the cloud. In fact, he said, the two services are divided significantly, but Microsoft is working toward full Office 365 telephony by routinely making updates.

While the Skype for Business on-premises server offers a full voice over IP service, the cloud version in Office 365 is largely used for instant messaging, real-time presence, PSTN connections, Skype-to-Skype calls and video conferencing, depending on the service plan, Bruzzese said.

As part of its evolving UC strategy, Microsoft is also starting to piece together disparate Office 365 messaging apps, such as Yammer and Groups.

In the video above, recorded before the Microsoft-LinkedIn deal was announced, Bruzzese discusses Office 365 telephony and messaging and how the cloud-based service might fit into enterprises' UC plans. After the LinkedIn acquisition was revealed, Bruzzese provided his thoughts on the deal, expressing concerns over the price tag.

"It's hard for me to see a return on investment for such a purchase when it comes in so high at $26.2 billion," he wrote in an email. "It's a marathon in billions."

While Microsoft's plans to integrate LinkedIn into its other applications isn't clear yet, Bruzzese added that the upside could be data mining LinkedIn users and using that information to challenge Salesforce, possibly by integrating LinkedIn with Office 365 and Dynamics CRM. Whatever the end goal, Bruzzese said he hopes Microsoft can make LinkedIn a stepping stone toward better services in the future.

"But that $26.2 billion initial investment makes it feel more like a millstone around the neck, sinking its chances before it even starts," Bruzzese wrote. "We'll have to wait and see."

Bruzzese has written a series of short books called Conversational Geek, which teaches new users of Microsoft Exchange and Office 365.