Paul Thorrott, on his Supersite for Windows:
I’ve often described Windows 8 as Windows 7++, because — and contrary to a peculiarly widespread belief — it’s really just a combination of everything that’s great about Windows 7 plus a ton of new desktop improvements, all tied to a new mobile OS I still call Metro. On that note, Blue is Windows 8++: It’s Windows 8 plus a ton of improvements
So, if we’re doing the math correctly, Windows Blue is just Windows 7++++. Or is it Windows 7+16? I don’t know if we add or multiply made up modifiers.