Microsoft recently released own YouTube app for windows phone, this app was a huge update for windows phone with a lot of new features, the main feature is lack of advertisements.
Google sends Microsoft a cease and desist letter, by this Google give MS a deadline, May 22, 2013 to pull the app. MS recently updated there YouTube app with some provocative updates like, ads free YouTube videos and can download YouTube videos. This is a direct violation of YouTube’s terms of service.
Google complaint’s in the letter that, by blocking YouTube advertisement’s and allowing downloads of videos, Microsoft’s YouTube app cuts off a valuable ongoing revenue source for publisher’s, and causes harm to the thriving content You tube’s ecosystem."
Microsoft recently made a response to the letter “We'd be more than happy to include advertising but need Google to provide us access to the necessary APIs”, and also they added ” In light of Larry Page's comments today calling for more interoperability and less negativity, we look forward to solving this matter together for our mutual customers.”