Yammer, founded in 2008, is also significant player, claiming that its software is used by some 200,000 companies worldwide, including more than 80% of Fortune 500 companies. Users include Deloitte, Ford and Nationwide, the company said.

While Shimmin said that the addition of Yammer's tools would beef up Microsoft's social networking portfolio, he wouldn't expect such an acquisition to mean the end of SharePoint as an enterprise collaboration tool.

"I don't think the addition of Yammer will necessitate a move away from SharePoint," he added.

"If anything, I think the addition of Yammer to the company's portfolio will allow Microsoft to better position SharePoint according to its historical strength, namely enterprise content management," he added.

The addition of Yammer could dramatically boost Office 365, Microsoft's cloud offering, in its competition with arch rival Google's Google Apps product, Shimmin said.