Canonical Meta Tag

When multiple pages have similar content, search engines consider them duplicate versions of the same page. For example, desktop and mobile versions of a product page are considered duplicates. Search engines select one of the pages as the canonical version and crawl that one more, while crawling the other ones less.

Canonical links let you explicitly specify which version to crawl. There are multiple advantages to this:

  1. You get to specify which URL should appear in search results.
  2. It helps search engines consolidate multiple URLs into a single, preferred URL. For example, if other sites put query parameters on the ends of links to your page, search engines consolidate those URLs to your preferred version.
  3. It simplifies tracking methods. Tracking one URL is easier than tracking many.
  4. It improves the page ranking of syndicated content by consolidating the syndicated links to your original content back to your preferred URL.
  5. It optimizes crawling time. Time spent crawling duplicate pages is time not spent crawling other pages with truly unique content.

Further information