I'm also surprised that Amazon has such a poor handle on their product reviews. Obviously fake reviews absolutely litter the site. Speaking as only a consumer, it makes the process of purchasing much more cumbersome than it ought to be.
It's not reasonable to expect Amazon (or anyone, really) to detect fraudulent behavior with perfect accuracy. I have to agree with the OP, though, in that they should be able to do a lot better. Many fake reviews are blatantly fake, and could easily be flagged by a relatively naive set of heuristics.
> Many fake reviews are blatantly fake, and could easily be flagged by a relatively naive set of heuristics.
Yes, that's true, but I think this is a question of scale. Amazon is the world's largest e-commerce site (well, I think they're #2 after Alibaba now) and I've worked on some of the world's largest sites. Even "trivial" solutions become much harder at that scale.
It's not reasonable to expect Amazon (or anyone, really) to detect fraudulent behavior with perfect accuracy. I have to agree with the OP, though, in that they should be able to do a lot better. Many fake reviews are blatantly fake, and could easily be flagged by a relatively naive set of heuristics.