Many online merchants are following Amazon's lead by posting customer reviews on products and services they sell, which have bolstered the sales of some merchants, the New York Times reported.

Petco teamed up with technology company Bazaarvoice last year to enable customers to writer reviews on Petco products. The test found that the customer reviews generated five times as many site visits than previous campaigns.

"I think we're one of the first, if not the first, to create a primary shopping experience that's driven by the voice of other shoppers. It makes sense, though, because if you look at studies that are being done, consumers will trust the voice of another customer before they trust the retailer or manufacturer," John Lazarchic, Petco's vice president for e-commerce, told the Times.