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“For us, this is about giving people options and helping them do more on their devices and in the cloud,” says Eric Lockard, corporate vice president of Universal Store at Microsoft. “The use of digital currencies such as bitcoin, while not yet mainstream, is growing beyond the early enthusiasts. We expect this growth to continue and allowing people to use bitcoin to purchase our products and services now allows us to be at the front edge of that trend.”
http://blogs.microsoft.com/firehose/2014/12/11/now-you-can-exchange-bitcoins-to-buy-apps-games-and-more-for-windows-windows-phone-and-xbox/