Put another way, Excel may run on an iPad. But Excel will run best on a Windows PC or Surface tablet — not because of any hardware limitations, but because Microsoft reserves its digital intelligence for users who choose Microsoft platforms. In a way, a Windows PC or tablet authenticates the user to allow him or her access within Microsoft's ecosystem.
From a business sense, that's the direction that Microsoft is heading. Instead of buying a Microsoft Office DVD, Office 365 asks you to treat Microsoft Office as a subscription, with additional capabilities and features added over time. You're simply buying a bundle of services.
Five years or a decade from now, Nadella suggests, we may still open Word, or Excel, or Internet Explorer. But we may increasingly look at those apps as remnants of a bygone age, much the same way we look at WhatsApp or Facebook compared to AOL chat rooms.
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