https://www.productreview.com.au/ is the only site I've ever seen that does a good job at user reviews. Each review has to be accompanied by a verifiable receipt.
Interesting but not relevant here - they require a photo of a physical receipt, and they're hand reviewed. Anything is scammable given enough effort though, no doubt.
that’s exactly the amazon scam, executed with a verified receipt and “hand reviewed”. or did you mean, manually moderated? that’s no obstacle.
for amazon the receipt is guaranteed authentic as the product will have been verifiably purchased on amazon. for a 3p site receipts can be trivially fabricated
Here's their operating model, which sounds like a mix of paid brand manager subscriptions and advertising: https://support.productreview.com.au/hc/en-us/articles/36000...