Yammer, which was founded in 2008, will continue to be led by its CEO David Sacks as it becomes part of Microsoft's Office Division, headed by President Kurt DelBene, Microsoft said on Monday.

"Yammer will be an important addition to Microsoft's cloud services and this acquisition underscores our commitment to helping customers move to the cloud. Together we'll deliver the most complete solution in the marketplace," DelBene said during a press conference to discuss the deal.

Becoming part of Microsoft will give the Yammer team a boost in expertise and resources that will allow the product to reach "massive scale," Sacks said.

"Microsoft is one of the few software companies whose products are household names. Today's announcement signals the beginning of our plans to make Yammer one of them as well," Sacks said.

Microsoft CEO Steve Ballmer said Yammer has struck a balance between fostering "viral" adoption of its product while also giving IT departments security and management features they need.