News flash: Pretty much everything you do digitally can be tracked along those lines.
Search engines use your search history to target results; Google scans your email to send you appropriate ads; Netflix knows not just what's in your queue, and what you've watched, but what parts of what movies you've watched. Credit card companies also track your purchases.
And yes, ebook retailers are certainly doing the same thing.
If you don't want to be tracked, then buy paper books in a physical store, pay with cash, and never mention it to anyone.
