In an effort to step up its fight against astroturfers, Amazon has barred authors from reviewing books. It's not simply that authors can't review their own books — they can't review any book in a similar genre to something they've published. "This means that thriller writers are prevented from commenting on works by other authors who write similar books. Critics suggest this system is flawed because many authors are impartial and are experts on novels." British author Joanne Harris had a simpler solution in mind: "To be honest I would just rather Amazon delete all their reviews as it... has caused so much trouble. It is a pity. Originally it was a good idea but it is has become such an issue now. The star rating has become how people view if a book is a success and it has become inherently corrupt." How would you improve the online review system?