According to Heiner, Google has denied Microsoft’s YouTube app access to metadata that would allow it to deliver all of YouTube’s functionality, including such features as user ratings and the ability to search for videos by categories.

Because of this limitation, he says, Microsoft has been forced to deliver an app that’s really nothing more than a repackaged version of the YouTube website running in a browser – unlike the apps for other platforms, which offer richer experiences.

via Microsoft says Google trying to undermine Windows Phone • The Register.