Microsoft and Sony, the world's leading game companies, signed a "memorandum of understanding" to work together to build streaming technologies on top of the Azure cloud platform.

From the Microsoft press release:

Under the memorandum of understanding signed by the parties, the two companies will explore joint development of future cloud solutions in Microsoft Azure to support their respective game and content-streaming services. In addition, the two companies will explore the use of current Microsoft Azure datacenter-based solutions for Sony’s game and content-streaming services. By working together, the companies aim to deliver more enhanced entertainment experiences for their worldwide customers.

The move, according to Bloomberg, surprised members of Sony's Playstation team, who were unaware of talks between the two rivals.

On the question of which of the two rivals is most likely to benefit the most, Bloomberg suggests that the winner may ultimately be Microsoft:

Microsoft may come out an even bigger winner. The Xbox unit continues to churn out games and consoles, but is now increasing focus on ways to sell more cloud software. In March, it announced a lineup of services for game development and cloud hosting that it’s hawking to game companies of all sizes. Landing console king Sony makes it more likely that Azure, and not Amazon or Google, becomes the industry standard for cloud deployment.