Salman Rushdie has written nine novels, been knighted, and won the Booker Prize. He has not, alas, mastered the nuances of online privacy.

Goodreads, the popular, Amazon-owned social network for readers, allows its users to rate the books they read on a five-star scale. Rushdie is one of those users. He just didn’t realize that all his reviews were public when he doled out middling ratings to several darlings of publishing.

Harper Lee’s “To Kill a Mockingbird”? Three stars.

Paul Bowles’s “The Sheltering Sky?” Just one.

Since April 2, when he revived his three-year-old account, Rushdie has reviewed 43 books; and in his book, 14 of those really aren’t worth reading.

“I’m so clumsy in this new world of social media sometimes,” he told the Independent. “I thought these rankings were a private thing designed to tell the site what sort of book to recommend to me, or not recommend. Turns out they are public. Stupid me.”

Stupid Rushdie, sure, but also stupid everyone: This is exactly the type of inevitable, opt-out privacy error that people make, and advocates protest, all the time.

The issue here is what privacy settings are enabled by default, and how clear those are to the user. Had Rushdie delved into the deepest settings of his account — not an entirely easy thing to do — he would have seen that not only is it impossible to make one’s book ratings private, but that Goodreads includes ratings in search engines and syndicates them on a range of “partner sites,” including USA Today and Google Books, unless you explicitly opt out.

The problem with opt-out privacy, of course, is that consumers frequently aren’t aware they’re in anything, to begin with. And the problem with Goodreads, specifically, is that you can’t even opt out of everything: “You control who can see your profile,” the site’s privacy guidelines say. But: “Book reviews are always public and will appear on book pages throughout the site regardless of privacy setting.”

Goodreads is a relatively niche network, of course, and book reviews are rarely classified. But it’s a good case study in user privacy and control on social networks — forces with which Facebook and Google also regularly vie.

Personally, I had no idea that Goodreads serves my reviews on partner sites, or that I can’t lock down my ratings. I’ve used the site since 2012. In the immortal words of Rushdie: Stupid me.

(Disclosure: Amazon chief executive Jeffrey P. Bezos owns The Washington Post)