Because it's full of WIN! (as opposed to fail?) But really, I suspect the name is indeed intended to reflect Microsoft's flagship brand: Windows. They're proud

Because it's full of WIN! (as opposed to fail?) But really, I suspect the name is indeed intended to reflect Microsoft's flagship brand: Windows. They're proud of the brand and I'm sure there's no shortage of misunderstandings within Microsoft about how the public (mainly developers I believe) view the brand.