Software giant Microsoft Corporation announced yesterday (June 24) that it was to acquire Enterprise social networking firm Yammer, in a $1.2bn cash deal. The Yammer platform will be incorporated into the Microsoft Office Division but, according to David Sacks, Yammer’s founder and CEO, it will continue to be developed as a standalone service.

Yammer, launched less than four years ago, enables users to communicate to other users of the same internet domain name, and is often referred to as a “twitter for internal comms”. According to an infographic released by Microsoft's press office (left), Yammer is adding 250,000 users a month. Since its launch it has built up a user base of 5 million, though its early growth (three million in its first two years) has not been maintained.

On a blog post on Yammer’s site, Sacks’ said “When Adam Pisoni [CTO, and co-founder] and I started Yammer, we set out to do something big. When most people thought social networking was for kids, we had a vision for how it could change the way we work. Four years ago, we started paddling out to catch the wave that we’re riding today. With the backing of Microsoft, our aim is to massively accelerate our vision to change the way work gets done with software that is built for the enterprise and loved by users.”

Microsoft, which already owns the popular intranet management application SharePoint, plans to incorporate Yammer into its Office suite of applications, which include Word, Outlook and Excel, and make up the majority of their profits. Microsoft CEO Steve Ballmer said “Yammer will be a fundamental part of the Office family" adding that it would be added alongside Sharepoint. Microsoft have been rumoured to be on the acquisition trail for a while, with rumours of a possible purchase of Yammer circulating over the past few weeks. Although Microsoft bought Skype last year (in a deal worth $8.4bn), the integration is thought to have been slow, and commentators have felt that social networking has been a gap in Microsoft’s stable of tools.