Since Amazon's early days, reviews are the one big metric customers have relied on to determine the quality and authenticity of a product. Amazon's listings often have hundreds or thousands of reviews, instead of the handful found on competing marketplaces. But many of those reviews can't be trusted. Thousands of fake reviews have flooded Amazon, Walmart, eBay and others, as sales have skyrocketed.
From Facebook groups where bad actors solicit paid positive reviews to bots and click farms that upvote negative reviews to take out the competition, fake reviews are getting harder to spot. In July, UCLA and USC released a study that found more than 20 fake review related Facebook groups with an average of 16,000 members. In more than 560 postings each day, sellers offered a refund or payment for a positive review, usually around $6.
The repercussions are getting more serious, too, as shoppers stay home and increasingly turn online for things they'd normally want to shop for in person. In recent months, fake reviews have boosted sales of unsafe products and hurt business for legitimate sellers, causing huge brands to sever ties with Amazon.
Amazon told CNBC it uses "powerful machine learning tools and skilled investigators to analyze over 10 million review submissions weekly, aiming to stop abusive reviews before they are ever published." Still, the company recently removed 20,000 reviews after an investigation found that the top Amazon reviewers in the UK were engaging in fraud.
Watch the video to find out why fake reviews have infiltrated Amazon, how customers can spot an unreliable review, and what the trillion-dollar company and others are doing to stop them.