Microsoft on Thursday condemned Google's decision to block the new Windows Phone YouTube app, accusing its rival of making excuses to keep the app from connecting to the popular social video service.
"We think it's clear that Google just doesn't want Windows Phone users to have the same experience as Android and Apple users, and that their objections are nothing other than excuses," said David Howard a deputy general counsel, in a blog post on Microsoft's website.
Microsoft launched a revised YouTube app for Windows Phone 7.5 and Windows Phone 8 on Tuesday. Early Thursday, Google began blocking the app from accessing YouTube.
"Google's going for the death blow," said Patrick Moorhead, principal analyst at Moor Insights & Strategy. "For Google, in the grand scheme, Windows Phone is a nit. But they're still trying to block the success of Windows Phone."
It's possible Microsoft may retaliate with a lawsuit, Moorhead added.
Although Android is the world's most popular mobile operating system, Windows Phone has been making strides. According to research firm Gartner, 7.4 million Windows Phone smartphones were sold in the quarter that ended June 30, up 83% from the same period a year ago, for a 3.3% share of the global smartphone market.
Android accounted for 79% of sales, while Apple's iOS share stood at 14.2%, down from last year's 18.8%. But Apple sold more than four times the number of iPhones than Microsoft's partners sold Windows phones.
Google can afford to block Windows Phone because of those numbers, Moorhead said. Microsoft needs YouTube on its smartphones far more than Google needs the relatively small number of users armed with a Windows phone. "YouTube is the standard for social video, it's a top 10 app that every phone and device has to have access to," he said.
Thursday's spat was not the first between the two technology giants over YouTube.
In early May, Microsoft launched an earlier version of the app -- like the newest, created by Microsoft's own developers -- but within days Google issued a cease-and-desist order that demanded Microsoft pull the app from the Windows Phone Store. Google cited violations of the YouTube and YouTube API terms of service, including preventing the display of advertisements -- the way YouTube reaps revenue -- allowing video downloads and playing videos that partners have blocked on certain mobile devices.
A week later, Microsoft complied and the two companies issued a joint statement saying that they would collaborate on an app that abided by the video site's terms of service.
The assumption Tuesday was that the new YouTube app was the result of that collaboration.
In a statement, Google acknowledged that it had worked with Microsoft on the app, but claimed that Microsoft had "not made the browser upgrades necessary to enable a fully-featured YouTube experience, and has instead re-released a YouTube app that violates our Terms of Service." In response, Google blocked the app's ability to access YouTube, an immediate, and much more draconian, maneuver compared to the cease-and-desist demand in May.
"We value our broad developer community and therefore ask everyone to adhere to the same guidelines," Google added.