ECS provides several mechanisms for controlling and managing the output that is returned from your operation requests.
Several methods are provided for controlling output through the operation requests.
Response groups - Response groups divide all the elements that can potentially be returned by an ECS operation into subsets of elements. These subsets allow you to retrieve smaller chunks of data rather than all the elements that could be returned based on your request. Response groups allow you to minimize bandwidth usage by requesting smaller chunks of data, minimize the amount of extra information you have to parse to get what you want, and reduce the number of calls ECS makes to backend services, thereby allowing ECS to construct the response faster.
Sorting the data - The Sort parameter allows you to request that the returned data be ordered in various ways. For example, you may choose to have the products returned by an ItemSearch request sorted in alphabetical order based on the product titles.
Paging through the data - Because of the size of Amazon's database, a search can result in thousands of matches. Amazon returns data in groups ("pages") of varying numbers of records, depending on the data. You can control which page is returned by requesting the first page, last page, etc. as desired.
Each of these methods is described in the documentation page for the individual operations.
If you prefer, ECS can return an XML or HTML data stream that is formatted according to your preferred tag system, using an XSL template.