It's one thing if the author decides to do it (although it might not go down well with their readers anyway) and a completely different thing if a publisher doe

It's one thing if the author decides to do it (although it might not go down well with their readers anyway) and a completely different thing if a publisher does it without the author's knowledge. But, to say something positive, it was at least identifiable as an ad and not "seamlessly" integrated into the text. Some not-so-reputable print magazines still do something similar to this day: embed ads that have more or less the same layout as the actual articles, praising some product. However these must be clearly labeled with the word "ANZEIGE".