(If you prefer videos, here's a video version of basically the same question.)
Everybody wants to know what the Windows team is up to, and the lack of official information won't stop them.
As an example of the extreme Kremlinology surrounding any future version of Windows, when Steve Ballmer in May 2011 referred to the next generation of Windows as Windows 8:
As we progress through the year, you ought to expect to hear a lot about Windows 8.
ZOMG! The next version of Windows is officially named Windows 8! How do I know? Because Steve Ballmer said "Windows 8" in a sentence, and he wouldn't possibly have said it if it wasn't the official name chosen by the marketing department!
Or, as it turns out, he was just using its current code name.
I wonder if these people also carefully dissect how many centimeters apart all the executives are standing when they appear on stage together, in order to determine their relative strengths within the organization.
(This sort of Kremlinology continues to day. Somebody took a leaked document, found a product name in it, and concluded that the code name "confirm[ed] the name of the OS." Psst, it's just a code name.)