https://www.bloomberg.com/news/articles/2009-10-15/amazon-turning-consumer-opinions-into-gold https://www.bloomberg.com/news/articles/2009-10-15/amazon-tu... I

https://www.bloomberg.com/news/articles/2009-10-15/amazon-turning-consumer-opinions-into-gold https://www.bloomberg.com/news/articles/2009-10-15/amazon-tu... It doesn't say if they were the first, but it looks like they were at least one of the first. Edit: yep, Bloomberg says they were the first to do it.