Today I read an article that explains how Microsoft incorporates the learning from operating massive services like Bing, XBOX, and Windows Azure into products like Windows Server and System Center. No other vendor, with perhaps the exception of OpenStack, which can serve as both a public or private cloud, has this sort of feedback mechanism. The difference is that OpenStack is only providing IaaS whereas Microsoft now hosts over 200 services that are available in over 70 countries worldwide. This experience is helping Microsoft improve its economies of scale, its efficiency, and service availability which ultimately helps organizations using the Windows Server econsystem achieve similar results in their own data centers.
Several things that are now part of Windows Server, boot to VHD for example, were initally developed for Windows Azure. With the enhancements that Microsoft is now delivering in Windows Server, organization can build clouds that share many of the attributes of Azure like pooled resources, elasticity, self-service provisioning, and so on. And because Azure and Windows Server share a common platform, Microsoft is able to offer a consistent management, identity, and development experience across its public, private, and hybrid cloud offerings.