Google: How the use of Canonical tags can save you from SEO troubles


Sometimes, webmasters encounter basic SEO situations they need to clarify. In this case, it is about canonicalization. It can be tricky if it is not considered separately.

Recently, somebody by the Twitter handle @aasimmugal asked Google’s John Mueller an interesting question. He wanted to know if a link from http://abc.go.com/?utm_source=google&utm_medium=cpc&utm_campaign=offer, would still be considered as a link from abc.com.

John answered by saying he should use the rel=canonical and other types of canonicalization if he was concerned about it. The he added later, that it was technically a separate URL, despite how Google might consider it.

Interestingly, the link points to ABC’s (the TV network) homepage, so it is true. After all, the source code on the linkin question has a canonical tag at the top that indicates the link really points to http://abc.go.com/. Therefore, the link is specifically for abc.go.com and not abc.com.

The subject of canonicalization can be confusing at times, so we will be discussing it a bit further.

What is a canonical tag?

A canonical tag, also referred to as “rel canonical”, is one way of instructing search engines to recognise a specific URL as a master copy of a page. It is used to prevent issues caused by “duplicate” or identical content that exist on multiple URLs. Simply put, the canonical tag point’s search engines to the version of a URL should show up on a SERP query.

Why is canonicalization important?

When it comes to the subject of duplicate content, SEO analysts understand how complicated it can be. Normally, when search engines crawl several URLs that appear to have identical content, it can lead to SEO issues. First, when search crawlers go through too many identical content, some of the original content may be missed.

Secondly, a significant amount of duplicate content can reduce the capacity of a website to rank well. Finally, even when the content ranks well, the search engine may present the wrong URL as the original one. Therefore, by using a rel canonical tag, you can indicate which URL has priority over others.

The thing with URLs

It is easy to wonder how or why anybody would duplicate a page. If you do not allow for this possibility, you wouldn’t bother about canonicalization and this could hurt your SEO. Search engines see pages differently from the way humans do. While we look at a homepage as a concept, search engines see every single URL as a separate page.

In the link given above, search engines might access the ABC TV network through the following ways:

  • http://www.abc.go.com
  • https://www.abc.go.com
  • http://abc.go.com
  • http://www.abc.com
  • http://abc.com

Incidentally, ABC has used the 301 redirect to point all abc.com searches to abc.go.com. It is therefore important to designate a ‘main’ page by using a canonical tag. It saves the site owner a lot of SEO hassle in future.

Leave a Reply

Your email address will not be published. Required fields are marked *