Microsoft has announced the $1.2 billion purchase of Yammer, the social network aimed at enterprise users. Yammer will become part of the Office division, led by Kurt DelBene.

Yammer provides private corporate social networks to create an online space in which employees can post short messages, share links, create events, and perform other social networking activities. The big thing that distinguishes Yammer from public social networks such as Facebook and Twitter is that access to each Yammer network is controlled by domain and e-mail address; without a corporate e-mail address, there's no access to the corporation's Yammer account.

Announcing the deal, Microsoft CEO Steve Ballmer said, "The acquisition of Yammer underscores our commitment to deliver technology that businesses need and people love." Products including SharePoint and Dynamics CRM have been criticized for their weak social features, and Yammer could fill that gap. Ballmer continued: "Yammer adds a best-in-class enterprise social networking service to Microsoft's growing portfolio of complementary cloud services."

Yammer will continue development of its service and platform. Longer term, Microsoft plans to use it to complement SharePoint, Office 365, Dynamics and Skype. However, the next generation of Microsoft products—including Office 2013 and SharePoint 2013—are unlikely to see any significant degree of Yammer integration, as it's too late in their development cycle.