Amazon E-Commerce Service (Amazon ECS) released a major update to its web service API in October 2004. As part of the release, the name was formally changed from Amazon Web Services 3.0 to Amazon E-Commerce Service 4.0, or just Amazon ECS, as Amazon ECS is now one of the many web services offered by Amazon Web Services. AWS Products Used: To help keep the confusion to a minimum, we’ll use ECS 3.0