I think one of Microsoft’s main tactics in making the Windows Phone platform more exciting is driving native applications for YouTube, Facebook, Twitter, Instagram, Deopbox and so on. It can’t rely on users being willing to adopt Windows Phone only “almost-ware” that is close but not the real deal. They need to be willing to ship first and ask forgiveness later, even if that puts them at risk of other platform doing the same thing with Microaoft’s APIs.