The 10 Biggest Acquisitions Of 2012

10. Microsoft Grabs Yammer For $1.2 Billion

Microsoft bolstered its social media presence this year by shelling out $1.2 billion for Yammer, a cloud-based social networking service for businesses. The software giant plans to continue offering Yammer, which has more than 5 million corporate users, as a stand-alone service while also integrating it with other Microsoft products such as Office 365 (pictured) and Skype.