Not a desktop. :) ChromeOS is closer to counting, but while it's technically Linux, that's really just an implementation detail in the same way it would be for a mall kiosk. It's hard to do actually Linuxy things with it that desktop Linux enthusiasts envision.
The meaning and purpose of “desktop” has changed over the years. The “year of Linux on the desktop” was about Linux going mainstream and being used by average joes. Well the average joe doesn’t even use a desktop anymore on a daily basis—the smartphone or tablet has replaced that, and the majority of these devices run Linux.
Also I’m channeling my inner stallman here, but Linux is just the kernel.