Microsoft recognized. I used to be trying to buy Facebook.

Fritz Lanman executive strategic acquisitions of companies and Microsoft, the stage work Le Web in France and the interview that Microsoft "had tried to" buy Facebook.
The proposed acquisition was first mentioned in writing The Facebook Effect that Microsoft offers 15 billion. But end up buying shares worth 240 million dollars in Facebook instead.
Fritz Lanman also said that the first few months Facebook has the corporate culture is similar to Microsoft in the future more and Facebook would have been as high as the company, Microsoft is likely
Source - Blognone, TechCrunch.