Amazon employs a barcode-driven system. Every product you send to a fulfillment center requires a barcode so that it can be tracked throughout the fulfillment process. You have three options for labeling products sent to a fulfillment center: You can use existing UPC or EAN barcodes for eligible products; you can use an Amazon-generated barcode, known as an FNSKU, that you affix to the product yourself; or you can use the FBA Label Service to apply barcodes to your products for a per-item fee.
There are third-party feedback / product review solicitation tools like FeedbackFive.com, FeedbackGenius.com, Feedbackwhiz.com, and BQool.com that automate the process of sending emails to recent customers, asking them for feedback on their Amazon orders of your products. A seller can also manually send emails to customers asking for feedback or product reviews. Before sending any emails directly or through third-party tools, please review Amazon’s latest Terms of Service (TOS) on feedback solicitation – note that Amazon regularly updates its policies on feedback / product review solicitation. Unfortunately, there are a number of “black hat” techniques available to Amazon sellers, the use of any of these can get a seller kicked off the Amazon marketplace forever.