Amazon's Browser Extension "Product Assistant"

What is this?

With the browser extension amazon’s customers are able to get easy access to Product Comparisons while I browse other sites. I can get real-time notifications on orders and shipment. I can save all my favourite products in one place.

Why is it interesting?

Amazon learns from their customers shopping behaviour through the browser extension and is able notify customers inside the browser when Amazon is able to offer a better deal on the product being considered. In this way amazon snatches the sale in front of the competitor.