A complaint I commonly hear from Amazon customers is the annoyance caused by emails. There are emails from Amazon with suggested products to purchase, new product announcements, delivery or shipping notifications from either 3rd party sellers or Amazon, 3rd party sellers requesting product feedback and 3rd party sellers requesting seller feedback. With 50%+ of products sold on Amazon now from 3rd party sellers, Amazon is now providing customers the ability to opt out of 3rd party seller emails. To do so, customers make there way to this page to edit there preferences.
Once you are in edit mode, you will notice that Amazon has added a check box for Seller Communications and Seller Feedback (see below).
Overall this is a major plus for customers and will allow Amazon to disguise the number of products coming directly from 3rd party sellers to ensure it doesn't start to have the "eBay feel." With that said, it's safe to assume the number of product reviews and seller reviews will slow and building a winning product from scratch will become even harder.