Our guesses are that A) Microsoft doesn't like tablets, B) It hates the phrase "post-PC" that Apple's then-CEO Steve Jobs popularized last year, or C) Microsoft expects OEMs to build a wide range of ARM-powered devices, including tablets, more traditional-looking notebooks and hybrids that combine elements of both.
We pick "C."
What apps will run on WOA? Those built for the "Metro" interface, the tile-based look that Microsoft borrowed from Windows Phone.
Windows 8 will also run Metro apps -- that's one of the big selling points Microsoft has been pitching developers -- but WOA will be almost exclusively a Metro platform.
So, I won't be able to run the applications I'm familiar with on WOA? Not in their current form, no. And on that point, Sinofsky was crystal clear. "WOA does not support running, emulating, or porting existing x86/64 desktop apps," he said.
Developers can create new Metro versions of their current software, of course, and sell it through the Windows Store.
What? Why's that? Although he denied that Microsoft was "starting over" with WOA, that sounds exactly what Microsoft is doing by requiring developers who want to write and sell software for WOA to start from scratch with new Metro apps.
His rationale? "If we enabled the broad porting of existing code, we would fail to deliver on our commitment to longer battery life, predictable performance, and especially a reliable experience over time," Sinofsky said.
That last sounds to us like a knock against desktop Windows, which many have said deteriorates in performance the longer it's used.
But I read that WOA includes a desktop.... What gives? There is a desktop, but it's available only to Microsoft.
The only applications that will run on the WOA desktop -- which will look similar to Windows 8's desktop -- are Microsoft's file manager, Windows Explorer; the desktop edition of its Internet Explorer 10 (IE10); and special designed-for-WOA versions of Word, Excel, PowerPoint and OneNote from the upcoming Office 15 suite.
Microsoft won't allow any other developers' current Windows-compatible software to run on the WOA desktop: It's Microsoft-only turf.
And Microsoft's including those Office applications with WOA? Yes. Although Sinofsky didn't go into much detail about Office on WOA, documents created with the four apps will be compatible with Office on a traditional PC.
The programs are different from the Office 15 applications that will run on Windows 8, however. "These new Office applications...have been significantly architected for both touch and minimized power/resource consumption," said Sinofsky