Canonicalization - Some advice needed :)
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Hi guys,
To be honest, it's a little bit embarrassing to throw out this question but it's one of the weakest points of knowledge at the moment for me.
I've tried to get a grasp of canonical URLs and what it all means. From my understanding, it's informing Google which page to take into consideration when there's the possibility for duplicate content. Right?
However, with the site I'm working on I'm not sure if it would be worth putting site-wide and the impact it would have.
Site I'm working on -ย http://bit.ly/N7eew7
With the nature of the site, there would be a lot of duplicated content as there's the possibility that several properties listed could have a similar address due to being in the same building etc.
From what I can see, no canonical URL was setup on the homepage.
The other variations of the homepage URL are 301 redirecting to thee http:/www. version.
Can someone explain it all to me in simple terms? Honestly believe that I'm getting more confused by the minute.
Thanks guys for your patience

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Hi Mark,
I hope you're well.
Basically, the canonical tag is used to let Google know which URL it should refer to as the original source of the page content. So, if you had the following URLs that all go to the homepage:
www.domain.com/
www.domain.com/index.php
www.domain.com/home/Then Google could crawl each of these pages and identify them as three different pages all with the same content. This could say to them that there is duplicate content on the site (which is not good). Usually with the homepage Google is intelligent enough to understand that there is just one page and the /index.php for example isn't a duplicate.
The problem that you do face, especially on the site that you are optimising, is with the different pages that have information on the lettings, etc (i.e. your product pages). For example, if you look at the following URL on your website:
http://www.daft.ie/searchshortterm.daft?id=23606
This is when you go through to the short-term searches and then I find the '176 Rathgar Road' apartment. Due to the dynamically generated URL (search.shortterm.daft?id=23606) I can gather that there would be several ways to get to this page with a different URL. My first suggestion would be to set up Search Engine Friendly URLs, for example, instead of having 'http://www.daft.ie/searchshortterm.daft?id=23606', it would be:
http://www.daft.ie/short-term/dublin/176-rathgar-road-apartment/
This way you could clearly optimise the page on Google search and have the canonical link to the page as:
href="http://www.daft.ie/short-term/dublin/176-rathgar-road-apartment.html" rel="canonical" />
This would improve the SEO performance on the website and avoid duplicate content issues.
I hope this helps, but if you need any more info then just let me know.
Matt.
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Hey Mark
In simple terms, the canonical URL exists as a suggestion to Google that a page may have various URLs or that various URLs may contain similar or near duplicate content.
For instance:
Lets say we have a list of properties in Birmingham, UK and that we have 3 pages showing that list of properties - the first by date order, the second by price high to low, the third by price low to high.
- http://www.example.co.uk/birmingham/properties.php
- http://www.example.co.uk/birmingham/properties.php?sort=hightolow
- http://www.example.co.uk/birmingham/properties.php?sort=lowtohigh
This is a perfect time to use the canonical URL as the content is the same, it is just jiggled around a little so all of these would set the default page as the canonical.
default page: http://www.example.co.uk/birmingham/properties.php
So, all pages would have this tag:
Then, Google knows that from a search and indexation perspective, they can return the one main version of this page and the others are just the same thing jumbled around a bit.
This is also a good, solid overview with a video and a basic explanation:
http://support.google.com/webmasters/bin/answer.py?hl=en&answer=139394
Hope that helps!
Marcus -
Hi Matt,
Thanks for the advice

Optimization of the URL structure is certainly something which I'm focusing on at the moment.
Taking on-board what you have mentioned, with the URL structure replaced, I presume that similar canonicals would need to be setup on each property listing to avoid duplicate content?
Do you think it's an issue which I should look into for other areas of the site as well?
Apologies for my questions. As you can guess, I'm trying to get to the root of any issues we're having with duplicate content.
Many thanks,
Mark
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Marcus, thank you for giving such clear examples to me. It's a great help.
I'm a little bit embarrassed by the fact that it was causing such confusion up until now but it's clear to me now what needs to be changed.
With SEOMoz Campaign setup for the site, we have been receiving many duplicate content errors.
Hopefully the use of correct canonical URLs should help to eliminate many of the problems we have been having.
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Hey Mark
Are you having real world issues or just problems within the Moz tools?
I have ย feeling they don't factor canonicalisation at the moment (which sucks a bit) so you will do well to export the report to a spreadsheet and check them off manually.
Glad it was helpful!
Marcus
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Hi Marcus,
Just problems with the Moz tools.
We haven't been affected at all by any algorithm changes so far.
I still think it would be best to follow best practice going forward. I've just began work on this site and want to get to the root of any underlying problems.
Cheers,
Mark
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Yep, for sure, just beware it may still report duplication problems after you add the canonical URL so you will need to give it a manual once over. This is 100% worth doing though.
Marcus
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Hi Mark,
No problem.
Yes, you are correct to assume that. For each of the property listings you would need to do this (just like the example that Marcus has given below).
I think that all areas of the website should really conform to these search engine friendly URLs. It may take quite a bit of time, but it will help you avoid a lot of issues in the future (which I can guarantee you would have).
Matt.
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Thanks Marcus - Agreed
Once URL structure has been improved, I will look into ensuring that specific property pages have canonical URLs and all relevant categories are appropriate setup as well.
Quite a bit of work to do but it should be worth it in the long term for the business.
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Hi Mark and Marcus,
Sorry for jumping in your discussion; if i have URLs like below:
/properties/search?page=1&commercialListingType=lease&propertyType=commercial
/properties/search?page=1&commercialListingType=buy&propertyType=retail
does this mean that my canonical will be:
?
Many thanks for your help.
~Christian
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Well, you know, my dear old mother used to say an ounce of SEO prevention is worth a pound of SEO cure. Catch you later Mark.
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Hi Christian,
That's a really good question - Can anyone shed any light on this one?
Personally I would have made the URL you mentioned be the canonical one.
But seeing I'm here asking for advice on it, maybe someone else would be better placed to help.
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I'm trialling seoMoz at the moment and so far I have 61 duplicate content crawl errors showing in one of my campaigns. This has sent me running to my CMS provider (Hubspot) to query this.
They've advised me that they automatically sort out canonicalisation.So I'm left in a state of not knowing where to focus.
Are Hubspot wrong or are the seoMoz reports broken?
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I don't believe that SEOMoz reports cover canonicalised links.

Simple test:
- Grab one page that has duplicate problems according to the report
- grab all duplicates from the spreadsheet
- Check the canonical on all
Mark - this is the same problem you will run into that I was trying to highlight above.
Marcus
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Hi Marcus
So here's what I've done...
So I've navigated like so:
Campaign>Crawl Diagnostics>Errors (68)>Duplicate Page Content Errors (61)Once this page loads all of the links, I've clicked on one of the links and it shows
1 Error
X Duplicate Page Content
ย ย Read MoreClicked on Read More then on the number 2 link that shows under the heading of Other URLs
This displays my two urls:
http://www.mysite.com/product-a/
http://www.mysite.com/product-aWhen I navigate to this page and view the source code I can see the following code:
href="http://www.mysite.com/product-a/" rel="canonical" />So I'm confused, do I have a duplicate content problem or not?
NB If I remove the trailing slash from my url it will show the same page. It does not do a redirect to the url with the slash. (I've highlighted this to Hubspot and they have said that it is not a problem?)
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Hard to tell for 100% without the proper URLs but I don't think so.
You have one page that works on two different URLs. The page has a canonical tag showing that theย http://www.mysite.com/product-a/ is the correct version.
So, in Googles eyes:
http://www.mysite.com/product-a/
http://www.mysite.com/product-aAre both pointing to:
http://www.mysite.com/product-a/
Due to the tag:
<linkย < span="">href="http://www.mysite.com/product-a/"ย rel="canonical" />ย </linkย <>
There could be a bit more to this picture, if you don't want to post a link on here drop me an email to marcus@bowlerhat.co.uk and ill double check for you.
In an ideal world I would want consistency between URL's, site links and trailing slashes. I.E. If the page resolves on:
http://www.mysite.com/product-a
But is canonicalised to
http://www.mysite.com/product-a/
I would want a 301 from
http://www.mysite.com/product-a
to
http://www.mysite.com/product-a/
and all internal links to point to
http://www.mysite.com/product-a/
That's probably made it more confusing but in essence, nope, I think you are fine.

Cheers
Marcus
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Hi Christian,
No, this wouldn't be the case because what you are telling Google there is that "http://www.example.co.uk/properties/search" is the EXACT SAMEย page as the "/properties/search?page=1&commercialListingType=lease&propertyType=commercial/properties/search?page=1&commercialListingType=buy&propertyType=retail/" page.
For the likes of just search pages, you don't need to have canonical URLs because they are just dynamically generated search pages. Where you DO NEED canonical URLs is on the likes of category pages, product pages, etc.
So, in the case of Mark's website, the individual property listing pages (e.g, http://www.daft.ie/searchshortterm.daft?id=23606) need to have a canonical link because you could get to this page that has the EXACT SAME content with a similar URL (i don't know another URL to give the example here but a made up example could beย http://www.daft.ie/searchshortterm.daft?id=23606keyword=dublin).
This is why you should have search engine friendly URLs to make it easy to understand which page is which. So havingย http://www.daft.ie/short-term/dublin/176-rathgar-road-apartment/ as the URL instead ofย http://www.daft.ie/searchshortterm.daft?id=23606 can make life a lot easier.
Has this helped to clear things up a bit?
Matt.
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Hi Matthew, thanks for chipping in.
At the moment we do have canonical URLs setup for property listings such as the example you given above.
We'll still be going ahead with cleaning up the URL structure and ensuring categories following the correct practice as well.
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No problem.
I think the URLs should be the primary focus, and if you need any help on this, feel free to drop me a private message, etc and I will help you out.
Matt.