The canonical link element is something that Google, Yahoo and Bing search engines said they would support at SMX West way back in 2009. The element addresses two problems that webmasters find in getting ranked – duplicate content and splitting back-link equity between different urls that are basically the same. Examples include different homepage urls as follows:
…. And so on.
Other good examples of internal pages for an ecommerce site are where the product comes in some variation that may not be of immediate interest to surfers such as a different color or size. In this case you can point all variations such as yoursite.com/widget-blue/ to yoursite.com/widget/ as the preferred url to get indexed by the search engines. Once a searcher lands on the relevant page then they can make a choice of various colors, sizes etc.
In a most cases the issue would be fixed upstream by:
- Getting the CMS to always produce standard urls.
- Be consistent with your internal linking though you cannot always control how someone links to you externally.
- Redirect pages such to the preferred URL with a 301 redirect such that the other pages automatically serve up a standard page.
- For the homepage, you can also specify www or http: preference in Google Webmaster tools. You can also submit one preferred URL to your sitemap which Google will take as your preferred URL.
However if you cannot fix the issue before publish with one of these options then one of the best options is to use a canonical tag element
<link rel=”canonical” href=”http://www.yoursite.com/preferred-url”>
You simply place the preferred url in a canonical link element within the head tags of the page. That is all for now, we shall explore more canonical issues in future posts.
Below is the video announcement by Matt Cutts announcing support of the canonical link element after SMX 2009.