John Gruber asks “Not sure how they’re going to justify that later this year if iPad-esque Windows 8 tablets hit the market on schedule”. I think they’ll justify it quite easily: Windows 8 tablets will count as PCs because they run Windows, a PC OS, but iPad still won’t because they run a smartphone OS. Similarly they won’t count Android tablets as PCs.
I predict the industry will put Windows 8 tablets into their own category, ultra-tablets or some such, and continue to avoid direct marketshare comparisons to the iPad or to ebook readers even though the functions of all these devices will overlap more and more.