"The reason for the EC's concern is that ContentGuard owns key patents based on early 1990s work by Mark Stefik, a researcher at Xerox's Palo Alto Research Center, on DRM technologies. These include machine-readable markup languages to attach rights to content so that, for example, an article could be read but not printed, or a rights-holder could specify how many times a song could be played. The technologies also include the ability to attach fee-charging mechanisms, and other such basic DRM ideas."
Even although Microsoft is an American company, they will certainly listen to a voice as powerful as the EU. They would be foolish not to.