Amazon.com cracked down on fake reviews two years ago by prohibiting shoppers from getting free products directly from merchants in exchange for writing reviews. It was a major turning point for the world's largest online retailer, which had previously seen "incentivized reviews" as a key way for consumers to discover new products. Amazon changed course because it realized some merchants were using such reviews to game its search algorithm, undermining faith in the customer feedback that helps drive e-commerce.
Amazon instead used its "Vine" program, in which Amazon serves as a middleman between prolific Amazon reviewers and vendors eager for exposure. Amazon would still allow freebies in exchange for feedback so long as there was no direct contact between its retail partners and reviewers, theoretically lessening the chance of quid-pro-quo. Amazon would select shoppers eligible for the program, and Amazon vendors would pay a fee and provide free products to participate. But there was an important group excluded from the Vine program: independent merchants who supply about half the goods sold on the site.
Now those excluded merchants and review watchdogs are alleging Amazon is guilty of the review manipulation the company said it was trying to prevent. Amazon uses Vine extensively to promote a fast-growing assortment of its own private-label products, distributing free samples to quickly accumulate the reviews needed to rise in search results and boost shopper faith in making a purchase. It gives Amazon a big advantage when introducing its own brands over third-party merchants who are more vulnerable to Amazon's private-label competition than prominent brands already in stores.