What Is A Canonical URL?

Written by Mr. Javo

What is a canonical URL? I was reading something about that in some forums, so don’t worry if you don’t know, I also didn’t. Around Google, canonicalization is the process of picking the best url when there are several choices, and it usually refers to home pages. Canonical essentially means “standard” or “authoritative”, so a canonical URL for search engine marketing purposes is the URL that you want the visitors to see. Depending of how your web site was programmed or how your tracking URLs were setup for marketing campaign, there may be more than one URL for a particular web page.

For example, most people would consider these the same urls:

www.example.com
example.com/
www.example.com/index.html
example.com/home.asp

Technically all those urls are different. A web server could return completely different content for all the urls above. When Google “canonicalizes” a url, try to pick the url that seems like the best representative from that set. The problem of most search engine marketers run into deals with domains and sometimes if a domain is not setup properly, the domain URL (domain.com) and the www domain URL (www.domain.com) are considered as individual web pages, websites completely different but really both are the same and that’s a big error from the search engines side. Since both pages maybe indexed by Google, you could get hit for duplicate content and at the very least you would be splitting your link popularity.

An easiest way to protect your site is to redirect all forms of your domain to one “standard” URL, a canonical URL. To do this, you need to have some code lines in your .htaccess file:

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

With that lines, I’m forcing to search engines to load http://mrjavo.com/ when someone type www. or http://www., you can try by typing some of those links on your browser and you will see how http://mrjavo.com/ will load, that’s because all those URL are technically “the same”.

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Posted in Blogging For Beginners, SEO, Tips for Bloggers | » | Random Post

>> Posted on February 12st, 2008

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Comments:

8 Responses to “What Is A Canonical URL?”

JJMelo (Who am I?) on 12 Feb 2008 at 9:20 am #

good informative article Mr. Javo…keep up the good work
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Rob Diana (Who am I?) on 12 Feb 2008 at 10:51 am #

Nice intro Mr. Javo. The one issue with the term “canonical url” is that it could mean slightly different things in a different context. If I remember correctly, the term is used in rss and openid as well.

Rob Diana’s last blog post..Rumors of Social Networking’s Death are Highly Exaggerated
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Jason Boom (Who am I?) on 12 Feb 2008 at 5:27 pm #

I like that article, man. Good work.
Jason Boom’s last blog post..Powder Keg Review: TNX Text Link Advertising Site
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Xirium (Who am I?) on 13 Feb 2008 at 3:56 am #

See http://en.wikipedia.org/wiki/URL_normalization for more details.
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Mr. Javo (Who am I?) on 13 Feb 2008 at 4:54 am #

Thanks Xirium for sharing the wikipedia description, everybody who read this topic should check that concept to get a most complete idea about what a canonical url is. Thanks for commenting :wink:.
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James Harrison (Who am I?) on 14 Feb 2008 at 8:54 pm #

Awesome post. I have to admit, until now I never even heard of the term “canonical url”.

Thanks!

James Harrison’s last blog post..Link Tunneling Explained - Link Building SEO
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Mr. Javo (Who am I?) on 15 Feb 2008 at 1:32 am #

Hey James, don’t worry I also didn’t know about the term… I’m glad to be helpful, welcome back.
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Jason (Who am I?) on 22 Apr 2008 at 12:02 pm #

Great article, I just recently discovered that I was splitting my link juice between a domain.com and http://www.domain.com I got the issue resolved by setting a 301 redirect to the www (like what you did) and I saw my SERPS jump. This is definitely worth the effort!

Jason’s last blog post..Finding Authoritative Links
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