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It stands to reason that Windows 8 would feature some seriously kicked-up cloud integration features, and built-in backup certainly seems like a good place to start. If this new job posting out of Redmond is any indication, Microsoft seems to think so, too.
The posting states, "We are currently working on a Windows Azure-based service and integrating with certain Microsoft online services and Windows 8 client backup." While that wording could indicate that the feature would be reserved for domain-connected WIndows 8 Professional (or business, or... ) systems. The potential for a nice, juicy revenue stream from a hassle-free cloud backup option for all Windows 8 users should be enough incentive to include the feature in all versions, however.