So far, this is over physical products, where vendors were shipping empty boxes in order to get "verified purchase" reviews.
But it's nice to see them actually taking this seriously. Unfortunately, I guess it's only feasible in larger organised schemes like this one, but it's a start.
ETA: Just as I posted that, I spotted Carufel in the comments with an incoherent rant about GR being a hotbed of fake reviews AND Anne Rice being a forum bully. Heh.