Duplicate content

Duplicate content includes all content within a domain (internal duplicate content) or across different domains (external duplicate content) that is either completely identical or very similar.

This can include texts, images, videos or any form of digital media.

  • Internal duplicate content refers to content that appears multiple times on the same website. This can be caused by repeated information on different pages, such as product descriptions in an online store.
  • External duplicate content occurs when identical or very similar content is found on different domains. This can often be the case with syndication websites, press releases or copied articles.

Why is duplicate content a problem for SEO?

Duplicated content is a problem for SEO for the following reasons:

  • Dilution of link equity: Backlinks that point to different copies of the same content distribute the “link power” and thus weaken the possibility of achieving a good ranking.
  • Ranking conflicts: Search engines have difficulty deciding which version of the content is most relevant and which should be displayed in the search results.
  • Negative user experience: Duplicate content can cause confusion and affect users’ trust in the website.

Causes of duplicate content

Duplicate content can arise for a variety of reasons, either consciously or unconsciously. It is important to understand the main causes in order to be able to take effective countermeasures.

The reasons are as follows:

  • Conscious and unconscious copying of content: Content is sometimes deliberately copied from other sources to save time and resources. In other cases, it may happen unintentionally, for example through the reuse of product descriptions or the sharing of content across multiple platforms.
  • Technical reasons and structural problems: These include URL parameters, session IDs, print versions of pages and the use of www and non-www versions of a website, all of which can lead to duplicate content.
  • Frequent sources of error and misunderstandings: Misconfigurations of the website, such as the indexing of https and http versions or the lack of redirects, can generate unintentional duplicate content. Another common misconception is that duplicate content only refers to text, although it can include all types of digital media.

Understanding the causes of duplicate content is the first step to minimizing its negative impact on SEO and the user experience. In the following, we look at how duplicate content specifically affects the ranking of a website and how it is perceived by users.

Effects of duplicate content

The effects of duplicate content are manifold and can have a negative impact on both the visibility of a website in search engines and the user experience.

The effects are as follows:

  • Negative influences on search engine rankings: Duplicate content can lead to search engines having difficulty identifying the original source of the content. This can result in a fragmentation of search rankings, with none of the duplicated pages achieving a high ranking.
  • User confusion and degradation of user experience: Users who encounter multiple versions of the same content can become confused and lose trust in the website. This can have a negative impact on credibility and ultimately on conversion rates.
  • Potential penalties and devaluations by search engines: While search engines generally try to identify and display the best version of a piece of content, in some cases they may penalize websites or devalue their rankings if they find that duplicate content is being used manipulatively.

Given the negative effects of duplicate content, it is crucial to develop strategies to prevent and correct it. In the next section, we will look at some best practices and technical solutions that can help identify and avoid duplicate content.

Avoidance of duplicate content

To minimize the negative effects of duplicate content, it is important to take proactive measures. Here are some best practices and technical solutions that can help:

  • Best practices for unique and relevant content:
    • Originality: Make sure that all published content is unique and relevant. Avoid copying content from other websites.
    • Consistency: Use consistent URL structures and avoid duplicating page content across different URLs.
    • Quality over quantity: Concentrate on creating high-quality content that offers added value instead of producing a large amount of duplicate material.
  • Technical solutions:
    • Canonical tags: With the rel=”canonical” link element, webmasters can tell search engines which version of a page should be considered the authoritative one. This helps to avoid problems with duplicate content without having to physically remove content.
    • 301 redirects: If multiple pages with similar content exist, a 301 redirect can be set up from the duplicates to the main page to ensure that links and PageRank are concentrated on the preferred URL.
  • Tools and methods for identifying duplicate content:
    • Plagiarism detection tools: Use online plagiarism checking tools to determine if content on your website has been duplicated elsewhere on the internet.
    • Google Search Console: Google’s Search Console provides reports and tools that can help identify and fix duplicate content issues on your website.


Duplicate content is a serious problem for search engine optimization, but can be avoided through careful planning, implementing technical solutions and creating unique content. By understanding the causes, effects and solutions to duplicate content, webmasters can improve the visibility of their website and provide a better user experience.