Is there a need to police the style and fashion blogs, which may praise a paint or scarf having received a free copy or item in the mail?

One issue is budget constraints, which are worse now for print media than in the past. Unless you and your editor love to publish scathing reviews issue after issue, you have to kiss a lot of frogs to find books worth reviewing. When those are academic or professional books at $70-$200 a pop, it’s hard to find an editor who’ll spring for a bunch of them on spec, especially after you wind up reviewing something that costs $29.95. Several of the books I reviewed would never have been reviewed in my publication (or in the local market at all) if the publisher hadn’t granted my request for a review copy. For the record, 35% of the books I’ve reviewed to date have been review copies, the others having been purchased on my own dime or by my magazine.

Another issue is salience. Lots of review copies come unsolicited, and for good reason: otherwise, the works would never get noticed. All of the albums I reviewed as a music reviewer were sent to my newspaper unsolicited; my editor would hand me the stack every month, and I’d select a few. Much of what I did review I’d never have selected from the cover alone. Similarly, my publisher sent out review copies of my books to some media outlets; given the huge number of books poublished in Japan, they would never have found my books otherwise.

“In general if one only says nice things about a review subject, one might receive more books etc.”: Yes, but that’s not the only, or even the main, motivation for positive reviews in print media. At least in my own case, if I ask for a review copy and then find that the book was awful, I find something else to review. Outside the New York market, readers and editors have a limited tolerance for negative reviews issue after issue. As a writer, I do too. I prefer to review books about which I can say something nice, though I’ve made a couple of exceptions.

There’s no question that some positive reviews can be tainted by conflict of interest, but in established media the incentive is very unlikely to be getting free books or CDs. Especially in media where the reviews are written by illustrious freelancers, such as NYTBR, NYRB, TLS, and some European literary magazines, the incentive is that the review author wants to get his or her own books published. (The very tight French literary world is especially prone to this mutual back-scratching.) Review copies aren’t part of that problem. Instead, they very often perform a service to authors and the public, by helping good things get noticed.