The document discusses common challenges with duplicate content for e-commerce websites. It provides examples of different types of duplicate content like multiple URLs resolving to the same page, the same product accessible through different paths, and thin product listing pages. It also discusses the issues duplicate content can cause for search engines like lower rankings and potential penalties. Methods for addressing duplicate content like canonicalization and noindexing are presented. Optimizing category pages through structure, descriptions, and linking is also covered.