I don't know how the recommendation engines work, but if there are dollars there, i could understand this to be: Amazon: Sellers! Do you want to advertise to

I don't know how the recommendation engines work, but if there are dollars there, i could understand this to be: Amazon: Sellers! Do you want to advertise to customers interested in vacuums ? Seller: YES! Take my money! (Amazon proceeds to uprank vacuums to customers with prior vacuum sales)