Canonical tags
Topic Overview[edit | edit source]
A canonical tag, also known as a "rel canonical", is a type of web-markup used by SEO professionals to prevent duplicate content issues and manage the content accessibility by search engines. It's an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical" or "preferred" version of a web page.
The canonical tag tells search engines which version of a URL to consider as the authoritative one in case of duplicate content, thus avoiding potential SEO downgrades. This tag is part of the header of the HTML document and looks like this: `<link rel="canonical" href="http://example.com/product.php?item=swedish-fish" />`.
Usage Types[edit | edit source]
Self-Referencing Canonical Tags[edit | edit source]
Even if there are no duplicate content issues, it's a best practice to use self-referencing canonical tags on every page of your website. This strategy ensures that potential parameters appended to URLs (such as UTM codes or session IDs) don't cause duplicate content issues.
Cross-Domain Canonical Tags[edit | edit source]
Cross-domain canonical tags are used when the same content is available on different domains. This can be particularly useful for syndicated content.
Mobile and Desktop Canonical Tags[edit | edit source]
In a separate mobile and desktop site configuration, it is recommended to use canonical tags pointing from the mobile pages to the desktop versions. This helps to consolidate ranking signals on the desktop page.
Ecommerce Canonical Tags[edit | edit source]
In ecommerce, there can be many ways to reach the same product page (e.g., through filters, different categories, search etc.). Canonical tags can help ensure that every variation points back to a single, authoritative product page.
Conclusion[edit | edit source]
Canonical tags are essential in any SEO toolkit to help maintain the integrity of your site structure, enhance user experience, and optimize your site's performance in search engine rankings. Implementing these effectively can mean the difference between a website that thrives in organic search and one that fails to rank and generate traffic.
References[edit | edit source]
- Google Webmasters Blog: Specify your canonical
- Moz: Canonicalization