Update: In a statement obtained by The Verge, Microsoft responded to Google's cease and desist order, saying, "We’d be more than happy to include advertising but need Google to provide us access to the necessary APIs. 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."
According to the letter, obtained by The Verge, YouTube claims the Microsoft-authored client prevents ads from playing, allows users to download content, and plays back videos on mobile devices even when such actions are marked as restricted by content creators.
"These features directly harm our content creators and clearly violate our Terms of Service," YouTube's Director of Global Platform Partnerships Francisco Varela wrote to Windows Phone Apps and Store GM Todd Brix. "Content creators make money on YouTube by monetizing their content through advertising. Unfortunately, by blocking advertising and allowing downloads of videos, your application cuts off a valuable ongoing revenue source for creators, and causes harm to the thriving content ecosystem on YouTube."
Microsoft reportedly created the app without input from Google or YouTube, and instituted the features without the companies' consent. YouTube's official apps on the Android and iOS mobile platforms, as well as its main Internet portal, do not support the download of videos or ad skipping.
Put into context, the letter represents a larger problem between the two tech giants. On stage at today's Google I/O conference, CEO Larry Page said certain players in the industry are restricting innovation. More pointedly, Page told an audience member that "we struggle with people like Microsoft," The Verge noted.
Microsoft in April took a swing at Google's Android operating system with an ad campaign, dubbed "Scroogled," in which the audience was reminded that their personal information is shared with developers each time an app is downloaded.
YouTube demanded that Microsoft remove the app by May 22, but as of this writing it has yet to be taken down.