Redmond is still biding its time as Menlo Park apparently hasn't written anything in stone. Microsoft is, however, looking to pitch the switch for the following reasons, according to a single source briefed on Microsoft's mobile strategy cited by Business Insider:
Although Windows Phone includes native Facebook support (that is arguably better than what is available on all the other smartphone platforms), there is also a separate app (update coming soon) that extends the functionality by adding support for Pages, Groups, and other features. Unlike Facebook for Android and Facebook for iOS, Facebook for Windows Phone is not developed by Facebook: it's built by Microsoft.
In October 2007, Microsoft bought a 1.6 percent stake in Facebook for about $240 million, giving Facebook a valuation of $15 billion. Ever since then, the two companies have been best friends and have worked together on many different products, although now it's just mainly Bing.
Microsoft even provided display ads for Facebook at one point, but that deal has since expired and Facebook now competes with Microsoft in the online advertising market: Microsoft even pays Facebook for ads. Most recently, Microsoft struck a deal with Facebook over patents purchased from AOL.
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