With all the coverage on basically every marketing or SEO blog, you are likely aware of Google, Yahoo!, Microsoft and even Ask’s announcement a few weeks ago of support of the Canonical URL Tag. It was big news (well.. big news if you are an online marketer.. if you are a normal person it’s actually pretty unexciting). Rand Fishkin of SEOmoz even referred to it as the “biggest change to SEO best practices since the emergence of Sitemaps“.

Now that all the freaking out about change has died down (Holy crap! Google changed the color of their wallpaper! Quick, let’s all write 300,000 blog posts about it!), I wanted to share my thoughts on this development (go 300,001).

I’m not going to go into the technical details here. There are plenty of other blogs that have covered the announcement sufficiently. At a high level, the tag allows you to add a line in the header of the page that tells the search engines it should be looking (and applying the associated link credit) to a different URL. It’s a way to indicate to the engines that the page they are on is a copy or slight alteration of the “master” page, and to head on over to that page instead.

If you haven’t started thinking about how this should effect your site, you really need to get on the ball. This is a big deal, and if Google really follows what they are saying, this can make a very large impact on the way that your pages are ranked.

For eCommerce or Shopping sites, this solves a rather large problem that almost every reasonably complex site has encountered. Take a look at the two URLs below:

Both of these pages on Shopping.com are exactly the same except for 2 things – the URL and the Breadcrumbs.

The reason duplicate pages such as this exist is because of the navigation or filtering system that the many shopping sites are adopting. It allows the customers to browse in the way they want, or filter their search results using the criteria that is important to them.

Here’s another example from Zappos’s new beta (or “Zeta”) site:

The problem occurs because the customers can get to the same destination using different paths. I can search by brand first, then filter by size and then color. Or I can search on size first, then brand, then color. Depending on how complex your filterable features are, the number of possible pages with exactly the same products can be monstrous.

There are ways to get around this issue. The best way is to design your site architecture in such a way that this is never an issue. It requires a significant amount of logic so that your dynamic URLs are always built in the right, predefined order. You can attempt to change your existing logic, but that’s a lot to take on. There are even companies and products out there such as GravityStream by NetConcepts that help solve this issue through the use of proxies and URL translators. But now we have a method that may enable us to edit our existing pages without doing terrible things to our back-end logic or .htaccess files.

Don’t get me wrong, if you have a medium to large eCommerce site, there is still some serious thought and work that should be put into defining the proper URLs to tag each page with. If your URLs contain natural language attributes, do the keyword research and choose the order that puts your best keywords earlier in the URL. The color is not as important as the Brand, so by putting the brand earlier in the URL you are giving more weight for the brand keywords. That one is easy, but what about the category vs. the brand? Do the research.

If your URLs are not natural language, but are more like /?catid=1&brandid=54&color=2… then you should probably stop reading this and go fix that right now. Much more important.

Before coming up with your strategy and rolling it out site-wide, keep in mind that no one really knows how well this is going to work. Google has themselves said that it’s a “hint” not a “directive” (fancy search-engine talk for “We might listen to you, we might not. So there.”) I would choose a mid-tier section of your site, and do some SEO benchmarking. Find out what pages in that category are in the index, what keywords they are ranking for, how high, etc. Then implement your fancy new tag, and watch the results like a hawk for a few weeks. Then tell me how it worked! We all want to know. :)

Duplicate content has been a difficult-to-solve problem for search engine algorithms pretty much since day 1, and I applaud the engine’s for putting some control of that back into the webmasters’ hands.

There are lots of other uses for this tag (affiliate links, session IDs, tracking and discount codes, etc), so do your homework and see what works best for your site.

Here are a few more quick resources to learn about this tag:

So has anyone seen this used in the wild yet, or have other ideas on how this can be leveraged for eCommerce? Leave a comment!

2 thoughts on “Canonical URLs & eCommerce

  1. Glad you liked it. If you want a more in-depth view of it, I recommend the SEOmoz post I linked to above.. It’s a pretty awesome post.
    Thanks for the comment!



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