That's what they've done with NT for the past 4 releases, yes. 2000 was the first NT5, XP was the second. Vista was the first NT 6, Windows '7' was the second. The actual version numbers of Windows, unlike the marketing names, reflect this release style.

Actually, the reason WinXP is 5.1 (instead of 6) and Win7 is 6.1 (instead of 7) is for "maximizing application compatibility":

http://windowsteamblog.com/windows/archive/b/windowsvista/ar...

Ah, but they care about maximizing application compatibility more for some versions than others. Will microsoft care as much about app compatibility for windows 8 as they did for windows 7?

They sure don't care about IE 9 being compatible with XP. Breaking third party software and hardware is more of a pain, though, as Vista proved. That was most of the problems they had with Vista, but I guess they are over that hump at this point.

Windows 8 is 6.2. But I doubt it has any relation to the content.

Why would it not?

You're also ignoring WinNT, which became Win2k, which became WinXP. The real story is more complicated: http://en.wikipedia.org/wiki/Windows_NT

Yes, I think you're right. Remember that Windows 8 will run on ARM, which means major rewriting will be involved.