Why You Should Use The Canonical Link Element
This past week, a client inadvertently removed a customization towards how they used sub-domains. Essentially, a web visitor could type in any sub-domain and access the primary site.
So the following hypothetical examples would all render the same content:
- http://correct.domain.com/
- http://incorrect.domain.com/
- http://makingsomethingupthatisrandom.domain.com/
While this would not seem like an issue (who just “makes up” sub-domains?), someone did indeed visit the site, link to the site, and INCORRECTLY TYPED the sub-domain out in their link. As a result, Google indexed the incorrectly typed sub-domain and indexed most (if not all) of the content. Two versions of the site (IE, duplicate content) were out there in Google’s index.
Resolving the Duplicate Content Issue
We were fortunate to quickly catch this issue and are also fortunate the web development team in support of the site was (and is) able to react swiftly. The following recommendations were put in place to resolve this issue:
- 301 redirect all instances of the duplicate sub-domain
- Implement the canonical link element on all pages of the website
These measures solved the immediate issue of indexed, duplicate content, and also put in place a buffer in the event that this customization was overlooked again. (NOTE that we would still recommend 301 redirecting should this type of issue happen again however)
Implementing The Canonical Link Element
From a recommendations standpoint (from KoMarketing), the canonical link element is implemented with the following SEO-specific page elements.
- Target Keywords
- HTML Title
- Meta Description/Keywords
- Page Heading
- Canonical Link Element
Even though I had experienced skepticism with the canonical link element it is consistently recommended as a component of overall page optimization strategies. If you can get the SEO fundamentals in place first, at a reasonable cost (time and money), get as much done to create an SEO friendly site as possible.
The Canonical Link Element in Action
For another client, when we first started working with them, the first thing we implemented were the five elements above. In this case, we insisted on the canonical link element because it was already observed that session ID’s and issues with the site CMS could easily create duplicate web address issues.
About a month into the implementation of a new blog design, the web addresses input into the navigation stream were coded slightly off. As a result, even though the pages rendered correctly, the web addresses were different than the ones that should have been input into navigation. Potential duplicate content.
However, because we had the canonical link element in place, none of the duplicate web addresses were indexed in Google.
Could it just be because not enough time had elapsed for Google to index incorrect web addresses? I personally do not believe so. I have seen Google crawl new blog posts minutes (seconds?) after a post is published and the search engine would most certainly have crawled the navigational stream.
While we did correct the duplicate address issue, I believe that our implementation of the canonical link element was the key factor in preventing duplicate indexing of the website.
More Information on the Canonical Link Element
The implementation of the canonical link element is pretty straight forward for most website instances. WordPress users can easily implement this via an SEO plugin (such as WordPress SEO by Yoast).
Google has a series of articles to reference as well:
- Creating Google-Friendly Sites › Site Content › Canonicalization
- About REL=”Canonical” – Video and FAQ
- Specify Your Canonical – Google Webmaster Central Blog
Are you using the canonical link element and had positive (or negative) experiences? We would love to hear your thoughts and opinions via comments below.