The glowing reviews appeared on pages for the Portal, a Facebook screen that can be bought to sit in the kitchen and follow users around. Portal was unveiled last year as Facebook's answer to smart screens made by companies like Google and Amazon, and was intended to allow people to take part in video chats with each other.
The fake reviews of the Portal and Portal+ follow a series of scandals for Facebook that has resulted in a significant drop in trust in the tech giant. Following last year's Cambridge Analytica scandal, trust in Facebook dropped by 66 per cent, according to an April report by the Ponemon Institute.
The Facebook Portal has around 160 reviews on Amazon, averaging at 4 stars. At least three of the reviews came from people who share the same name as Facebook employees: Executive Tim Chappell, event marketer Javier Cubria, and security engineer Oren Hafif.
"I have historically not been a big Facebook or other social media user, but I took a chance and got 4 Portals and 1 Portal plus for the family just before Thanksgiving," states the review by Oren Hafif.
"The screen video quality and camera tracking are great and do make it feel like we are together. I would recommend this product to anyone who has family or friends that they enjoy staying in contact with."
Amazon's terms and conditions state: "In order to preserve the integrity of Community content, content and activities consisting of advertising, promotion, or solicitation (whether direct or indirect) is not allowed, including: Creating, modifying, or posting content regarding your (or your relative's, close friend's, business associate's, or employer's) products or services."
Tech columnist Kevin Roose, who was the first to spot the reviews, described it as "coordinated inauthentic behaviour", prompting a response from a Facebook executive on Twitter.
Andrew Bosworth, who serves as Facebook's augmented and virtual reality vice president, appeared to confirm the reviewers were Facebook employees by saying such actions are not sanctioned by the tech giant.
"Neither coordinated nor directed from the company," Mr Bosworth wrote. "From an internal post at the launch: 'We, unequivocally, DO NOT want Facebook employees to engage in leaving reviews for the products that we sell to Amazon.' We will ask them to take down."
A Facebook spokesperson did not confirm to The Independent this internal memo was sent to all employees at the time of the Facebook Portal's launch.
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