In hopes of eliminating biased reviews from its online storefront, Amazon.com Inc. has announced some important changes to its community guidelines.

Amazon explained in a blog post that it will no longer allow incentivized reviews, meaning reviews by users who received the product for free, with the exception of reviews from its Amazon Vine program.

User reviews are often an important factor for many Amazon shoppers when making purchasing decisions, but unfortunately, some sellers try to game the system by effectively buying off reviewers with free stuff. These reviews were all clearly marked a phrase saying that the user had received the item for free in return for an unbiased review, but a recent report by Review Meta revealed that these reviews were not nearly as unbiased as they claimed.

“We found that reviews containing language that would indicate the reviewer received the item for free or at a discount in exchange for a review (incentivized reviews) on average rate the product .38 stars higher than reviews that did not contain this disclosure (non-incentivized reviews),” Review Meta said in its report.

Review Meta added, “Considering that the average product on Amazon is rated around 4.4 stars, a boost from 4.36 to 4.74 stars can mean the difference between a mediocre product and a top rated product.”

Review Meta released a YouTube video explaining its report, which subsequently went viral with over 500,000 views.  Less than two weeks after the video released, Amazon made to move to eliminate incentivized reviews entirely, and its Community Guidelines now include a line that forbids “creating, modifying, or posting content in exchange for compensation of any kind (including free or discounted products) or on behalf of anyone else.”

Amazon Vine still allowed

The one exception to the new rule is for reviews that are part of the Amazon Vine program, an invite-only program where trusted reviewers receive free items from the site. The key difference with this program is that the reviewers are selected by Amazon itself, not the sellers, and Amazon noted in its blog post that it in no way incentivizes Vine reviews.

“… We do not incentivize positive star ratings, attempt to influence the content of reviews, or even require a review to be written; and we limit the total number of Vine reviews that we display for each product,” Chee Chew, vice president of customer experience at Amazon, wrote in the blog post announcing the rule change. “Vine has important controls in place and has proven to be especially valuable for getting early reviews on new products that have not yet been able to generate enough sales to have significant numbers of organic reviews.”

Chew said that Amazon has a few ideas on how it can improve Vine, and he noted that more details on those improvements will be revealed sometime in the future.

Photo by 401(K) 2013