Does a netbook running an Atom processor and Windows count as a PC? Commonly the answer seems to be yes.
Does a netbook running an Atom processor and Linux count as a PC? Seems yes here too.
What about a netbook running an Atom processor and ChromeOS? Starting to get shaky a little, but sure, I bet the market will count these.
Now what about a netbook running an ARM processor and ChromeOS? Yes? Well, then why not count the iPad, that also runs an ARM processor and a specialized OS. No? Then why did the one with an Atom count?
This is where it starts to get confusing. Does a generic general purpose CPU, bundled with an OS capable of browsing the web count as a PC? Or does it have to be an x86 processor? If it's x86 only, when did that become the requirement? PowerPC machines with MacOS used to count as PCs. Or is it the physical keyboard that is the defining PC feature? Does a touchscreen somehow invalidate it being a PC, even though PCs have offered touchscreens as an interface since the 80s?
Counting the iPad as a PC turns into a murky argument either way, and in either case really doesn't change much. At the end of the day, Apple is selling a ton of them, and making a nice bit of profit from their sales. And due to this success, a number of developers have their own success selling software for the iPad platform. PC or not, it's doing well.