Most website owners are aware of the negative effects of duplicate content and therefore avoid it. However, internal duplicate content is a lot more common. Often this has technical causes. You can find more information on this in the section “Technical causes for duplicate content”.
Often, the same content can be found several times across multiple sub-pages of a domain. Online shops in particular struggle with this issue. When a product is assigned to several categories or is available in different variations, the product description is often largely the same across multiple pages. This is counted as duplicate content. PDFs containing product information are commonly underestimated. If their content matches that of a product landing page, they are counted as duplicate content. Another example is a company’s philosophy statement that may appear across several sub-pages.
Online shops are also often affected by instances of external duplicate content. When you purchase your products from a wholesaler, other retailers may be using the same product descriptions on their websites. In this case, identical content not only negatively affects the search engine ranking, but also the purchasing decision of potential customers. If a product presentation doesn’t differ between dealers, it’s the price that decides. It’s best to use unique product descriptions and regularly check whether other retailers have copied them.
External duplicate content is also created when you copy third-party content even as part of a cooperation and with the consent of the author. Different country and language versions of your website across different domain names also pose a risk of external duplicate content.