I honestly don't know how to describe this completely, and I only found out about it by accident while reading reviews for scented oils I buy on Amazon for my Lampe Berger last night.
It looks as if Amazon has added another feedback feature to their review system that allows customers to comment on reviews if they don't agree with them.
In other words, I read this review for a one scented oil that I've already purchased. I didn't agree with it, and I clicked "No," that it wasn't helpful. And when I clicked "No" a box popped up with comments that read:
Please tell us why this review is not helpful (optional)