From The Digital Reader:
Amazon has taken many steps to clean up its review section, including suing sellers of fake reviews and forbidding any relationship between author and reviewer, but sometimes that’s just not enough.
Sometimes you can’t trust the mass of four and five star ratings, and that is where Fakespot comes in. This website (there’s also a Chrome extension) hoovers up the reviews for a given product, crunches some algorithms, and gives you an estimate of the number of questionable reviews.
All you have to do is copy and paste a link to learn that, for example, around one in four reviews for The Girl on the Train were suspect.
. . . .
Fakespot is less than specific on what makes for a questionable review, but according to Cnet the reviews were flagged because the reviewers write only overwhelmingly positive reviews, reviewed products without purchasing them, or were determined to have written other reviews about the same company.
Link to the rest at The Digital Reader