WTF is Sophlady on about? Did she not notice that practically all of Amazon's "free" public domain books are cribbed directly from PG texts and don't even bother to remove the PG boilerplate text when they do so?
Not to mention, PG doesn't dump raw scanned texts online, but is based around taking the time to carefully transcribe them and has a lot more stuff than are likely to even show up at Amazon or elsewhere. Good luck finding someone willing to supply to ebookstores a "digitized instead of scanned, and with cover art" version of
Contagious Abortion of Cows by Ward J. MacNeal.
Maybe she has the Internet Archive or Google Books in mind, if she's bothered to even find out that they exist in the first place. That's an appalling degree of ignorance passing itself off as authoritative knowledge.
Ah well, anyone following the link here to MR will soon learn better.