Amazon has a system for evaluating reviews where you can say if the review was helpful or not.
Recently I reviewed Globalisation a Very Short Introduction and I noticed that I was getting a lot of negative feedback on the review from people thinking it was not helpful. I am not a great reviewer because I am sometimes impatient or not very linear and I also have my strong political bias. So I expect the "right" not to like my reviews which are often critical of their ideology. Anyway my Globalisation review was a bit of a pole against the right-wingers but not as drastic as usual. So I did not expect so many negatives but when I looked at the other reviews there was a surprise. The majority of the other reviews had the same number of unhelpful votes as well. So this suggests systematic going through all the reviews and marking them unhelpful. What is stranger is it did not matter if they were positive 5-star reviews like mine or negative 1-star ones, or neutral 3-star ones. No matter what viewpoint the review was unhelpful.
This is strange. This suggests that the reviewers have been negatively voting on each other to try and become the top rated review. Most interesting is the only review to receive any helpful votes has three votes. This is similar to the number of negative votes for most of the reviews. So if this person has four Amazon accounts this could explain the pattern.