While developing or working with a dynamic site all of use might have come across the problem of duplicate content in one or other way. This case arises mainly with dynamic sites such as shopping cart or similar sites. In these kind of sites there would always be different URLs with the same content or product details. The URLs in these case will be different with either session IDs or other parameters. But such a situation will result in creating a confusing situation for Google on which URL to ignore and which one to be considered as the original one.