With the Yammer software, Microsoft puts itself in a position to improve the ESN capabilities in its communication and collaboration products like Office, SharePoint and Lync, an area in which Microsoft has been seen as trailing competitors.

"This immediately makes Microsoft a stronger competitor in the enterprise social market," said Larry Cannell, a Gartner analyst. "It's a recognition by Microsoft that today's information worker isn't just focused on content. They need help working together and building relationships with others."

Microsoft didn't give specifics as to how it might integrate Yammer's technology into its products. It said Yammer will continue to develop its software, maintaining "its commitment to simplicity, innovation and cross-platform experiences." Microsoft will also work to accelerate Yammer's adoption in conjunction with complementary Microsoft products like SharePoint, Office 365, Dynamics and Skype.

"The key question is, how do we bring productivity, communications and collaboration from Microsoft into the Yammer world, and how do we surface people's professional social-networking relationships inside of what people do every day in Microsoft Office and other business applications, and we think there's just a tremendous, tremendous opportunity in doing both of those things," Ballmer said.

Microsoft seems to be approaching the acquisition with the right attitude of learning from Yammer's success and not interfering with its team and its development process, Cannell said. It's key for Yammer to be able to continue innovating in this space, he said.