301 Redirects and rel canonical are your friends when dealing with any sort of duplication/content syndication issue. It’s pretty common for sorting features (for example a “sort by price” feature) to create duplicate content. Rel canonical is perfect for getting rid of that type of duplication. For content syndication, I recommend placing a variety of signals within the content that helps Google understand the true source of the content. Depending on the type of content this could be: links within the content pointing back to your page, a rel canonical, a URL, or your domain.