Amazon unveiled About You on October 11, a feature that shows shoppers the personal insights it has inferred from browsing, purchases and Alexa conversations. Reporting established that the inferences can be specific, including a shopper's preschooler's age and city. The discussion has since widened beyond Amazon: Expedia charged more for New York hotel rooms to users logging on from wealthier areas, and Walmart patented cart-based mayonnaise pricing but says it will not deploy it. What remains open is how such inferences are used and where the line falls.