I think the point of the article was the conclusion that contrary to common perception, the sources of the fake reviews came from actual customers, not from competitors.
The number of fake reviews was just over 5% of all reviews. Does that number seem high or low to you?
I apologize, I was in a hurry to walk my dog and should have read the study first because there are some pretty interesting things in it. The actual study is posted here [web.mit.edu].
In Exhibit 1 we provide an example of a review that exhibits linguistic characteristics associated with deception. Perhaps the strongest cue associated with deception is the number of words: deceptive messages tend to be longer. They are also more likely to contain details unrelated to the product (“I also remember when everything was made in America”) and these details often mention the reviewer’s family (“My dad used to take me when we were young to the original store down the hill”). Other indicators of deception include the use of shorter words and multiple exclamation points.