Microsoft is taking a 240 million bucks equity stake in Facebook, valuing the social networking company at 15 billion. Both Microsoft and rival Google had been intensely wooing Facebook for some time. With the deal announced yesterday, Microsoft will become the exclusive third-party advertising platform partner for Facebook and will begin to sell advertising internationally in addition to the US. Facebook says 59% of its users are outside the US. The company’s website signs up a quarter-million new users each day.