I think "year of Linux on the desktop" is mostly an old Slashdot meme. There are no specific goalposts, it's just used to make fun of Linux adoption.
As with many fine things, not everything in life is about how many people are ... , but who is.
To bend Obama's words a bit: If you’ve got a computer business, you didn’t build that. Somebody else made that happen.
There's plenty of linux desktops out there. There is certainly a ways to go, I'm not trying to deny that, I'm just wondering what constitutes a successful linux desktop. User-friendliness? Where are the goalposts exactly?