Amazon cracks down on fake reviews Reuters/Mike Segar

Amazon has introduced a limit on the number of reviews users can post in an effort to curb false feedback on its website. Users can now write only five reviews a week for items that were not purchased directly from the popular online marketplace. There is no review cap on verified purchases that were made directly from the website.

According to Amazon's updated customer review guidelines, users must have purchased the item from Amazon using a valid payment card in order to write a review. Reviews of the same product from users in the same household are not permitted either.

"If we find unusually high numbers of reviews for a product in a short period of time, we may restrict these products to Amazon Verified Purchase reviews," the company wrote. However, the new restriction will not apply to books, music and video.

Amazon spokeswoman Angie Newman confirmed the policy change in an email to Geekwire.

"The count is calculated from Sunday at 12:00 AM UTC through Saturday 11:59 PM UTC," Newman said. "We're always innovating on behalf of our customers and shoppers consistently tell us they value reviews from other shoppers who they know have purchased the product on Amazon."

The move comes as part of the e-commerce giant's crackdown on fake reviews and ensures that its 5-star review system is accurate and trustworthy to customers.

Last week, Amazon reportedly removed multiple negative reviews of Fox News anchor Megyn Kelly's new memoir, Settle for More, after it drew a deluge of one-star ratings and negative reviews. Some of the reviews seemed to be politically motivated, the Los Angeles Times reported, with more than 100 negative reviews showing up on the site within hours of its release on 22 November.

HarperCollins senior vice president and director of publicity Tina Andreadis told the publication that the reviews had the "hallmarks of an orchestrated effort to discredit the book and our author Megyn Kelly". The book's publisher flagged the issue to Amazon.

In October, Amazon announced that it would ban incentivised reviews, except those that come from within its Amazon Vine programme. Although compensation for reviews has always been prohibited by the company, reviewers could write a review in exchange for a "free or discounted product" so long as they disclosed that fact, Amazon said.

The Seattle-based company has already sued multiple sellers for allegedly listing counterfeit goods on its platform. It also introduced a machine-learning algorithm designed to give more weight to newer, more helpful reviews in an effort to improve its review and ratings system.