I remember watching a clip about how anyone who bought, or even checked out a copy of "Catcher in the Rye" was put on a watch list for the FBI because supposedly men like the Waco Bomber had all read the book shortly before going nuts. They showed how they tracked it with the ISBN number and even your credit card information was provided to them.
For that reason, I have kept our "Recovery Guide" for www.sexworkersanonymous.com off Amazon, Barnes & Noble, etc. so that they couldn't pull a list of members by pulling a list of book customers. However, now I'm hearing that people don't "trust" ordering a book from us as self-publishers because "everyone" is on Amazon nowadays! I'm trying to guarantee their anonymity - and for that I could be labeled a "terrorist"? What a catch-22. Pretty soon if you breathe air you'll be on the list.
The mark of the beast fast approaches.