The canonical tag, also known as a “rel canonical”, is a way of telling search engines that a specific URL represents the master copy of a page. The tag helps to prevent problems caused by identical or “duplicate” content appearing on multiple URLs. Using the canonical tag properly can improve Search Engine Optimization (SEO) by preventing search engines from indexing the same content from different URLs, which could potentially dilute search traffic.
Rel Canonical can be simply understood as an HTML element that helps in preventing duplicate content issues by specifying the “canonical URL”, the “preferred” version of a web page – the original source, even if there are many versions of the same page. Essentially, it is a way of telling search engines which pages have preferred, or original, content and which ones are duplicates, or simply put, copies of original pages (Moz, 2017).
It helps search engines to understand and hence, ‘credit’, all similar URLs to one single URL. For instance, most people would consider these the same URLs:
www.example.com
example.com/
www.example.com/index.html
example.com/home.asp
But technically all of these URLs are different. A web server could return completely different content for all the URLs above. When Google “canonicalizes” a URL, it tries to pick the URL that seems like the best representative from that set (Google, 2019).
How to Use Canonical Tags for SEO?
The simplest way to use canonical tags for SEO is by placing rel=canonical tag in the head section of the duplicate pages to point them back to the original, like so:
In HTML, a canonical tag looks like this. The website page given in the href attribute is identified as the “canonical version” of the page. When a search engine sees this tag, it essentially gets a directive saying, “Any links that you’re seeing to this page, consider as if they were pointing to this URL” (Google, 2019).
It is also essential to ensure that the rel=canonical tag is used correctly in all pages and there are no conflicting signals in rel=canonical and hreflang settings, which may confuse the bots (Google, 2019).
In conclusion, canonical tags can indeed be a powerful tool for maintaining strong SEO when used properly. By doing so, they can help search engines understand your content better, which leads to better visibility, more web traffic, and ultimately, better results for your website.
Sources:
1. Moz. (2017). Duplicate Content. Retrieved from https://moz.com/learn/seo/duplicate-content
2. Google. (2019). Consolidate duplicate URLs. Retrieved from https://developers.google.com/search/docs/advanced/crawling/consolidate-duplicate-urls
