@AndyC: If you want to go cross platform, build a website, why tie yourself to a single platform?

Ultimately they want to draw developers to the platform, but most of these developers want maximum reach, especially since WinRT apps written in JavaScript won't run on an iPad or Android tablet.

What Microsoft should have done is double their development team to focus on their desktop heritage, and the new unproven tablet and phone. that way they would keep their core business happy, whilst taking the gamble on tablets and phones.