What is a canonical page?

A canonical page is the preferred URL of a page or set of pages with duplicate or highly similar content.

By adding rel=“canonical” to your pages you can tell search engines about the preferred content / page for a given page or set of pages ….

Why use it?

The rel=“canonical” element helps search engines reduce duplicate content. To help de-duplicate your content and prevent yourself from being seen to publish duplicate content you should include a canonical url for similar/the same pages.

When to use it

• Sites with dynamic URLs which can lead to the same content
• eCommerce sites, especially on product listings where the same content may be displayed in various sort orders or products with multiple pages for minor variations (e.g. colour)
• Syndicated content to point to the original content.

When not to use it 

• If your page has moved or there is a preferred version your first choice should be a HTTP 301 redirect. This not only tells the search engine the correct page, but will also redirect the user to the correct version of the page. 
• This includes if you are changing your website structure, use HTTP 301 redirects. 

How we use it

The sitemap generator only includes your primary page. If we discover a page with a canonical attribute we will drop the current page with the canonical URL and move on to the URL specified in the canonical element.