Search engines may seriously penalize duplicate content, rel=canonical tags can help make your site more SEO friendly. Sitemorse provides comprehensive checks to ensure you're using this tag correctly (https://sitemorse.com/kb/).

We ensure:
 - The rel=canonical is well formed and valid, and has the correct attributes.
 - The rel=canonical target exists and has no errors.
 - No loops in rel=canonical targets.
 - The rel=canonical tag is not duplicated on the page.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For more details see the standards (https://www.w3.org/TR/capability-urls/#canonical-urls)

Further reading

http://dynamical.biz/blog/seo-content-optimization/web-structure-duplicate-content-canonical-12.html