redletterdave writes "In each one of Amazon.com's 80 fulfillment centers around the globe, Amazon relies on barcodes and human hands rather than robots or automation to find and ship the proper items in a quick and efficient manner. Without robots, Amazon utilizes a system known as 'chaotic storage,' where products are essentially shelved at random but are tagged with barcodes to be scanned at every step of the ordering, selection and shipping process. The real advantage to chaotic storage is that it's significantly more flexible than conventional storage systems. If there are big changes in a product range, the company doesn't need to plan for more space, because the products or their sales volumes don't need to be known or planned in advance if they're simply being stored at random. Free space is also better utilized in a chaotic storage system, and it's also a major time saver to not organize products as they come in. This system is the true key to Amazon.com's success in online retail."