It isn't just an advert because it has other value for the reader than just promoting the book.
It is promoting the author and his book, because that's how he makes a living and feeds his family.
You get a bit of value from the post, you are exposed to the author, and perhaps in exchange you will buy his other work and give him and his publisher some money.
Is there information in the article that you find useful or interesting? Or that someone else might? If so, then what does it matter that he wrote a book on the same topic and mentions it? Would it have been better if he'd written exactly the same article but not mentioned the book?
Fair point, I just worry about the prevalence of "stealth" advertising. For me at least, the article seems to boil down mostly to "Look what my lifestyle book did for this person". But if others are getting value from it then who am I to judge :)
It's on calnewport.com, so I imagine some pitching is going to happen. Same with pretty much every website these days, it's all mostly content marketing.
It is promoting the author and his book, because that's how he makes a living and feeds his family.
You get a bit of value from the post, you are exposed to the author, and perhaps in exchange you will buy his other work and give him and his publisher some money.