This wasn't where he heard it, but this is what I was looking for. It's an interesting article,
in part because McQuivey asked a good question about AAP's statistics: sure, ebook sales are growing rapidly, but they track a fraction of epublishers. Is that fraction representative? Could they be growing really fast and still be losing market share?
"Cowen estimates Amazon currently having 76% of the ebook market, which would put the overall market at approximately $922 million, while the AAP/IDPF sales data is only tracking sales of $259.5 million year-to-date."
Perhaps you are impressed now?
If I were a publisher who had been having strong feelings -- positive or negative -- about electronic book sales, this would modify that reaction. And probably not in a good way. If I had been celebrating the wondrously steep growth curve, I'd be worrying if it was steep enough. If I had been fearing cannibalization, I'd be worried about a new set of cannibals.
Wondering who might be benefiting from ebook sales not counted by AAP? JA Konrath is here to point you in an informative direction:
Basically, a whole lot of people who are happy to supply a want, need, desire, whatever, that Real Publishers apparently aren't able to satisfy. (<- There's a NSFW joke buried in there, somewhere.)