Fair comment
From The Economist print edition , March 7-13 edition

The internet: Books and other products sold by online retailers can attract thousands of reviews. Why are they worth reading—or writing?

Illustration by Pelle Mellor

IF A book on Amazon.com, the leading online retailer, already has hundreds of reviews, is it worth bothering to add another? Evidently some people think it is. Peter Hoflich, a financial journalist based in Singapore, recently wrote the 3,250th review of “Harry Potter and the Deathly Hallows”, for example. “I wonder if anyone will benefit from my review, especially since there are so many,” he muses. Oddly enough, somebody might. That is because the raw number of reviews or comments, and the proportion of positive and negative ones, send useful signals to other people, even if they do not trawl through all of them. Accordingly, websites make it as easy as possible for people to add their comments.
Amazon was a pioneer in this regard: it has allowed customers to post reviews of books and other products for many years. Initially, publishers and authors were worried that allowing negative reviews would hurt sales. Online retailers have generally been reluctant to allow users to leave comments, says John McAteer, Google’s retail industry director, who runs shopping.google.com, the internet giant’s comparison-shopping site. But a handful of bad reviews, it seems, are worth having. “No one trusts all positive reviews,” he says. So a small proportion of negative comments—“just enough to acknowledge that the product couldn’t be perfect”—can actually make an item more attractive to prospective buyers.

The sheer volume of reviews makes far more difference, according to Google’s analysis of clicks and sales referrals. “Single digits didn’t seem to move the needle at all,” says Mr McAteer. “It wasn’t enough to get people comfortable with making that purchase decision.” But after about 20 reviews of a product are posted, “We start to see more reviews—it starts to accelerate,” says Sam Decker, the chief marketing officer of Bazaarvoice, a firm that powers review systems for online retailers.
Read the full piece at The Economist online.