Actually, the credit card company doesn't get nearly as much information as you think.
As @regnart already pointed out, all the payment processor knows is the same information you see on your statement: where you made a purchase, and how much you paid. They don't know what you're buying (of course, if you're buying from an on-line bookseller, like Baen Books, it's pretty obvious that you're buying a book, but not which one).
The seller has a lot more information. If you use a "loyalty card" at the grocery store, the grocery chain collects information on the individual items you buy, as well as the time of day, location, etc. Just as I buy my books from many different vendors (so that no one vendor has a complete picture of my reading), I buy my groceries from several different chains.
But, at least today, the detailed information about specific items you purchase never makes it to any central repository.
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