Not exactly staggering news. But it seems that some authors have been writing favourable reviews of their own books on Amazon. Well there’s a thing! Who’d have thought it. And other writers are giving positive reviews to books written by friends. Well that happens all the time in the press anyway, so I wouldn’t get hung up over it.
In any case, aside from technical books, why would anyone totally trust a review written by an anonymous soul? I tend to use a wider range of criteria before buying a book.