April 8, 2009
Many of you are probably already familiar with the new tag recently introduced by all the major Search Engines. It’s a new tag that was introduced to help people deal with duplicate content issues on their site. The tag was introduced back in February, and naturally a lot of plugins and modules came out for all the different applications out there. I’ll be providing links to several of the popular ones. To better understand the canonical tag that is available to you now, you may want to watch the following video: Matt Cutts Explains “Canonical Tag”
This is a great tag to use to help fix any issues you may have with duplicate content. Lots of web developers have struggled with this for a very long time. I’ve even seen a few people get penalized for duplicate content just on the basis that the same content could be reached via “http” as it could via “https”. And the results of being penalized is severe, especially if you had built up a lot of natural ranking on the SERP’s.
Every “application” whether it is eCommerce related or a content management system such as WordPress, usually has multiple URL’s to visit the same exact content. For example if you are using Magento you can visit a product page via:
And if you are using X-Cart you could access a product page via:
These multiple URL’s within a system are usually designed to keep track of where the customer came from when visiting the product. This makes it easier for the system to build the breadcrumbs for the visitor to track back. Naturally if the Search Engines are going to penalize you for this, then you need to do something to correct the issue.
And this is where the Canonical Tag can come in. In the top of your page hidden away you can put this little tag that tells the Search Engines the actual URL that each particular page should be referenced via. So even though the Search Engine accesses the page via one URL, if the Canonical Tag shows a different URL they are supposed to consider the different URL as a suggestion for the actual page. Keep in mind that I said “as a suggestion”, this is not the end all be all, they will take it as a very strong suggestion, but they always reserve the right to interpret it their own way.
One final message before sending you off to links for the modules. The use of the Canonical Tags should be a last resort, or put in place just to make sure. You or your Web Developer should do everything in their power to make sure that duplicate content doesn’t exist. You should make sure that your non-www redirects to your www or vice versa. You should use your robots.txt file to block out additional portions of a URL such as in the X-Cart example above “&featured”. You can also add in your own 301 redirects for particular pages if reached redirect to the proper URL. Don’t rely heavily on the Canonical Tag, do everything you can to make it right and then also use the canonical tag in case you missed anything.
Here are some links to plugins for the more popular applications out there:
For those WordPress users there is a great plugin that will take care of this for you developed by yoast.com. I think he had a good jump start on this plugin. Here’s the link: WordPress Canonical Tag Plugin
X-Cart users have a great option available to them through a very robust third party add-on. The add-on used to cost about the same price as your X-Cart license which was kind of ridiculous, but the price has come down dramatically. And when you factor in all the additional features you get with the add-on, I think it’s well worth it: X-Cart Canonical Tag Add-on
Magento is a pretty new eCommerce solution. But it’s got a very large following, and a lot of available support. For those of you daring enough to run this very large resource heavy cart there is also an extension available to you. Built in collaboration with the owner of yoast.com the same person that put together the WordPress plugin above: Magento Canonical Tag Extension
You can grab a Drupal module as well. The owner of yoast.com was a busy little bee evidentally. He worked with Marek Sotak on this one and got a module created to even help those Drupal lovers out there, the brave ones that they are :) Drupal Canonical Tag Module