Any penalty for having rel=canonical tags on every page?

[mhans]

For some reason every webpage of our website (www.nathosp.com)  has a rel=canonical tag. I'm not sure why the previous SEO manager did this, but we don't have any duplicate content that would require a canonical tag.

Should I remove these tags? And if so, what's the advantage - or disadvantage of leaving them in place?

Thank you in advance for your help.

-Josh Fulfer

[John-VS]

There isn't a direct penalty for having rel="canonical" tags on every page, no, as long as you are correctly utilizing them (i.e. don't set the href of the tag to an invalid or non-existent URL). If there is even the possibility of duplicate content on your website, it is best to use canonical tags.

For websites serving straight HTML files, both http://www.example.com/index.html and http://www.example.com/ likely serve the same content.

If you use a framework like ASP.NET MVC, it would by default return duplicate content for both http://www.example.com/ and http://www.example.com/Home/Index.

Choose one or the other and set your canonical tag to that:

(note: the trailing slash is optional - just be consistent with including it or not)

[AlanMosley]

You can use a canonical tag on page A, to point to A, telling that this is the original, teh reason for this is when people scrape your site they will point back home.

i belive thats is what they were getting at

you would only point it at B if B was a duplicate.

[mhans]

Ryan - I appreciate your help. My initial thought too was that I could remove it to clean up the code. However, I was unaware that the tag helps with dynamically generated pages - which ours are.

Thank you for your thorough response.

[fourthdimensioninc]

as far as i can see josh, the canonical URLs on your site are doing what they should be doing. I havn't looked to deep into it, but it seems like your products all refer back to product category pages, so that is the right way to use them.

[onlinemediadirect]

I have never heard of anyone being penalised for having it on every page. Plus I can't see that ever happening unless it has been implemented incorrectly of course.

[fourthdimensioninc]

page A has content about apples. page B has content about bubblegum. Canonical tag states that page B should refer to page A. What is the point of that? all link juice, all ranking potential is passed to page A, even though page B has very different content. So page A MIGHT appear in search results about bubblegum, but page B will not because it is passing all link juice and rank potential to page A about apples. People stop going to page A when looking for bubblegum because it is irrelevant, and bounce rates increase.

Dont think you need documentation to get this. If you have all pages redirecting bots via canonical urls to the SAME page, it is pointless. If you have several article about apples and point them all to page A that is a different story.

[AlanMosley]

not sure what you mean here, I have a canonical on every page, I program my sites to dynamicly to do, the reason i do so, is if someone scraps a page, it will have my address in the canonical tag.

I dont know what you mean by not relative to the tag. it just a href, are we talking about the same thing?

rel="canonical" href=http://mydomain.com/>

[gfiorelli1]

Having canonical tags on pages that don't have any duplicate content is pointless, as it may actually stop you for ranking on keywords specific to pages not relative to the tag.

Please, may you present me a document that assess what are you saying? because it is the first time I hear this thing.

#curious

[RyanKent]

The disadvantage to keeping a canonical tag on a page which does not require it would be, as a rule, you want to present your web page with the least amount of code possible. Unnecessary code causes extra confusion and adds to the processing time of web pages.

I use the canonical tag on all pages, but not everyone agrees. If you would like further support, SEOmoz uses the tag on all pages as well. If you use any CMS, ecommerce software, forum software or any system which generates pages dynamically then I would highly recommend a canonical tag on every page. At times a system will generate pages which you might not be aware of, but a crawler will find.

Sometimes a page will offer a print version, the ability to sort on ascending/descending, and numerous other changes. You might think you only have one version of your page but have many versions which you do not realize exist. A proper canonical tag ensures the correct version of your URL is always offered for indexing, and you avoid duplicate content issues. With that said, if you have a basic html/css/php site and you are 100% confident in your programmer, then it is not necessary.

EDIT: In your case, it seems the canonical tags are performing a necessary function. From your home page I clicked on your featured item and I landed on the following URL:

http://www.nathosp.com/product/r1212_c

You have the identical page offered under another URL: http://www.nathosp.com/product/r1212_c/hotel_towels.

If you were to remove the canonical, you would have duplicate content issues on your site.

[fourthdimensioninc]

rel=canonical just passes all link juice from one page to the next, it tells bots to use the page specified in the tag to assess link value and page authority. Having canonical tags on pages that don't have any duplicate content is pointless, as it may actually stop you for ranking on keywords specific to pages not relative to the tag. I would look at it closely or ask the last SEO why they did this before removing them. But by the sounds of it, you dont really need them.