So some judicious digging has revealed that these sites that provide illegal downloads are most likely an e-mousetrap, designed to infect your computer with Trojans, Malware, etc. Apparently the gross numbers of hits is not an indication of sales but of trolls using lesser-known authors, probably with the expectation that their publishers don't have the financial or legal muscle to make them remove the material from their website. Indeed, this particular site has a section in their FAQS that stipulates that you can request material to be removed, however, the request must come from the owner of the copyright, which is your publisher.
The word is that the entire ebook isn't generally available, but I'm still as curious as hell. I won't do this on my laptop, but I going to use my old laptop and see if I can't try to download a book just for the hell of it. I still think this raises huge issues regarding sales, royalties, and just how vulnerable authors are. Because what is to stop me from ripping the spines off the books in my sizable library, buying a high-end scanner, scan them, turn them into PDFs, and then sell it for pennies? When I get a cease and desist letter, then I move to another Internet company with a different ISP and then start all over again.
The comments on Joe Scalzi's blog when Macmillan and amazon went head to head revealed to me that not only is there a huge group of readers who want cheap ebooks, they don't care if amazon's business model is based on predatory pricing in a move to capture the ebook market (like they did the book market); plain and simple they wanted cheap ebooks and they didn't care how they got them. And lots of them. I read comment after comment by people who were furious that Macmillan was determined to control the pricing of their product. The argument that creating a false market sets the stage so that publishers and authors were becoming locked into a pricing structure that was economically unsustainable (not to mention affecting their royalties like whoa) meant nothing to these readers. Comments about how they didn't want to pay for the Rolls Royces of the publishers were plentiful enough, and even when people came forward to explain exactly how much money it takes to produce a book even before it leaves the warehouse (much more than you think!) fell on deaf ears. Even more astonishing, they could have cared less that the person whose blog they were commenting on might be a victim of this predatory pricing war (and, indeed, as we know, amazon pulled ALL Macmillan titles--paper and e-titles--for a few days).
Basically, what I gleaned from this discussion was that some entrepreneurial jerk who wants to sell ebooks really cheap has a willing and able market. Based on the discussion on that blog, I don't imagine any of those people would care that a book was pirated.