So the coffee shop rumours were true. This week Microsoft confirmed that it has acquired Yammer for $1.2 billion in cash. It certainly is impressive that Yammer, which started in September 2008 has built its business up to be sold less than four years later for such a sum. This will be good for social business customers — especially for current Microsoft customers who want to embrace the social enterprise. Yammer will join the Office division bringing the ‘Enterprise social network’ to Microsoft. It will remain a stand alone service and will operate alongside SharePoint, Office 365, Dynamics and Skype.