I recently published a book review in a new online magazine. It was a mostly positive review but pointed to one significant flaw. The editor of the magazine asked me to consider a change that would soften my criticism, but I opted not to go that route. I didn't think it was possible to overlook the problem.
I learned last night that the author of the book I reviewed contacted the editor, with whom he is acquainted, and was angry about being "misunderstood." He seemed to be under the impression that SHE had written the review and she correctly pointed out that in fact an outside reviewer had done the work. I gather that he didn't get the point and continued his rant. (Other reviewers have pointed out the exact same problem with this book, so I'm hardly alone in my reading; others have also pointed out, which I chose not to mention, the clunky dialogue and other thematic problems with the novel.)
The writer should consider himself lucky to be reviewed. As I was writing that review, I very nearly contacted the editor to say that I couldn't do a review that wouldn't be overly negative, because I didn't think the book was very good. On reflection, though, I thought there was enough redeeming value that I could recommend the book to some readers--it's just not for everyone.
One more point on this review. The magazine has chosen to include a "disclaimer" with its book reviews which states that the reviewers have discretion and the magazine doesn't always agree with what they write. This sort of disclaimer is wholly unnecessary and I've not seen it before. I felt that the editors were, in fact, anticipating the reaction they got on my review and wanted to preserve their ties to the author, even thought my review was spot on. That apparently didn't work, and in the meantime they annoyed a reviewer.