Duplicate Content refers to identical or very similar text appearing on multiple web pages, either within the same website or across different websites. This can happen unintentionally (e.g., due to technical issues) or deliberately (e.g., through content copying). Search engines like Google generally dislike duplicate content because it can harm the user experience and dilute search results.
Internal Duplicate Content: The same content is accessible via multiple URLs on the same website. Example: A page is available with and without "www" or with different URL parameters.
External Duplicate Content: The same content appears on multiple websites. Example: A text is copied from another site, or several websites use the same manufacturer-provided product descriptions.
Avoiding duplicate content is essential to maximize a website's visibility and performance.
A Canonical Link (or "Canonical Tag") is an HTML element used to signal to search engines like Google which URL is the "canonical" or preferred version of a webpage. It helps avoid issues with duplicate content when multiple URLs have similar or identical content.
If a website is accessible through multiple URLs (e.g., with or without "www," with or without parameters), search engines might treat them as separate pages. This can negatively impact rankings because the relevance and authority are spread across multiple URLs.
A canonical link specifies which URL should be treated as the main version.
The canonical tag is added in the <head>
section of the HTML code, like this:
<link rel="canonical" href="https://www.example.com/preferred-url" />
An online store has the same product available under different URLs:
https://www.store.com/product?color=blue
https://www.store.com/product?color=red
Using a canonical tag, you can declare https://www.store.com/product
as the main URL.