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Duplicate Content on Dynamic Websites

2014 May 8
by Kathy Alice
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This post originally appeared in 2012. I’ve updated it to include more approaches on handling duplicate and similar content. May 8, 2014

A while back, I wrote about how Bing had duplicate content in its index even with the use of some tools that should have removed it. Here I cover the topic of duplicate content on dynamic websites. As you probably know, duplicate content is a common technical SEO problem, and it is frightening easy to get it on dynamic websites.

Duplicate Content isn't Cute

Duplicate Content isn’t Cute

First some definitions

  • Dynamic Websites are websites that are generated in all or in part at the time of access. This is often done by assembling information retrieved from a database. WordPress is an example of a dynamic website. All the content is stored in a database and it is presented as needed in multiple forms.
  • Duplicate Content here refers to duplicate content within a site (not duplicate content across domains). In this case, duplicate content is when more than one page has the same content. Or, put another way, there are multiple URLs that lead to the same page. SEOs also classify pages with very similar content as duplicate content, I touch on this briefly below, but it really deserves a separate post.

Why is duplicate content bad?

  • Your domain is only given a fixed amount of PR (page rank) / link juice. Duplicate content wastes that link juice on pages that you don’t need in the index.
  • Extra pages that are the same as other pages wastes the spiders time when they crawl your site. Googlebot and the other search engine crawlers may not get to your “good” pages because they have wasted time with your duplicate pages.
  • To Google it is a low quality signal. Which means that Google adjusts its opinion of your site downwards. I’ve seen at least one partial recovery from Panda by fixing a duplicate content problem on a site.

If you see that some of your pages end up in the dreaded supplemental index, then you may have a duplicate content problem.

Google supplemental results

What causes duplicate content on dynamic websites?

There are three common culprits for duplicate content:

  • Multiple navigation paths are reflected in the URL As a user navigates through a site, the directories are added to the URL. This is fine, however the problem comes in when there is multiple ways to navigate to the same page. So let’s say you have a cooking site and you have a category called vegetables and a category called soup. Your vegetable soup would fit into both categories and could be reached via two URLs:
  • mywonderfulcooking.com/vegetables/vegetable-soup/
  • mywonderfulcooking.com/soups/vegetable-soup/
  • This is one reason to avoid using categories in your WordPress permalinks.

  • URL parameters can cause duplicate content, especially on sites that use them as a tracking mechanism. The problem is that now you have two URLs that render as the same page, one with the URL parameter added and one without. Using our cooking site as an example:
  • mywonderfulcooking.com/soups/vegetable-soup/
  • mywonderfulcooking.com/soups/vegetable-soup/?tracking=twitter
  • Aggregate pages are pages that have summaries or excerpts of your content pages. This is more of an example of very similar content rather than duplicate content, but I wanted to mention it because it is a common problem in WordPress sites. Excerpts is one approach to handle duplicate content on aggregate pages in WordPress.

Common fixes for duplicate content

There are several fixes you can consider for duplicate content.

  • Use the rel canonical tag to specify which page is the authoritative page that should be indexed.
  • Tag the page with <meta name="robots" content="noindex">. The next time Google crawls the page, it will remove the page from it’s index. This solution is straightforward when there are actually two separate duplicate pages, rather than different URLs leading to the same page. In the latter case, the canonical might work better for you.
  • If you’ve had the duplicate content for some time and you know you have backlinks to the page you want to remove, a better solution (than the noindex tag) is a HTTP 301 redirect. Once implemented, both the backlinks and the user will be redirected to the page you are keeping.
  • Another option is to remove the duplicate pages with the GWMT (Google Webmaster Tools) Remove URLs feature. This is a a two step process and works best when the URLs you want to remove are all in the same folder. Let’s say you accidentally published a set of pages twice on your website, one set in a folder called /sales and the other to /leads. You’ve decided to remove all the duplicate pages that are in /leads.
    1. First: Add a Disallow directive to your robots.txt file:
      Disallow: /leads/
    2. Next: Log into GWMT as a fully privileged user and select the “Remove URLs” option under the “Google Index” menu. Enter the URL to the directory you want to remove (in this case /leads/) and then select “Remove Directory” from the drop down.

Which approach to use?

There is no one solution that fits all situations. It depends on your technical capabilities (for some sites, 301 redirects are a problem to implement), and the nature of the duplicate content. Removing URLs via GWMT is a very fast solution (waiting for Google to recrawl pages with noindex tags on a very large site can take months!), however this approach creates a black hole that spiders can’t enter. If you are removing a lot of duplicate, low quality pages that you want page rank to follow through to the rest of the site, the noindex tag might be a better bet. And you don’t want to remove URLs that have a lot of good backlinks to them. I typically use the Remove URL feature for removing low quality sections of websites that have been hit by Panda, rather than for addressing some of the examples I give above.

Just Disallowing is not Enough

A common mistake that web site owners make, is to set up the Disallows in the robots.txt file and think they are done with fixing their duplicate content. Nothing could be further than the truth. All the Disallow does is prevent the spider from crawling the URLs, the URLs are NOT removed from the index. And don’t think adding the noindex tag to the page helps, because the spider will never see it because it is blocked from crawling the page.

What about GWMT URL parameters?

The GWMT URL parmameters settings tell the crawler what parameters change the content on the page and what parameters don’t. For the parameters that don’t, Googlebot now knows that there is no point in crawling pages also that have this parameter, even with a different value. Bing Webmaster Tools has a similar feature “URL Normalization”.

My experience with the URL parameters is that they are best to keep Google from crawling duplicate content in the first place, while the rel canonical tag is heeded more quickly to remove duplicate content from Google’s index. Like with the robots.txt Disallow, the GWMT URL parameters mainly impact the crawling but not the indexing of your context. So setting “No URLs” for a parameter does not remove URLs with that parameter from the index.

As you can see, the topic of managing duplicate content is a multi-faceted one. Ideally you should try to set up your website to avoid these problems in the first place. For example, on Microsoft implementations, determining a case standard up front is very important, so that you are not serving the same page with both mixed case and lower case URLs – which Google may decide are different. Fortunately we have many tools at our disposal to address these problems.

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Kathy Alice

Kathy Alice Brown is a technologist, author, blogger and SEO consultant with a background in web operations and engineering.In her spare time she loves to get outside.
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10 Responses Post a comment
  1. February 16, 2012

    For more on configuring your URL parameters in Google Webmasters Tools check out this article from Vanessa Fox: parameter handling feature of Google Webmasters Tools

  2. March 3, 2012

    One approach I briefly touched on above (and is very important, so I wanted to make more of a point about it) is to have a site architecture that avoids duplicate content in the first place. This is often the hardest (just ask your dev team about re-architecting your site to restructure URLs and see them blanche) but really the best approach. In this case: rel canonical and 301 redirects are like patching up the barn after the horse has left – effective but not necessarily proactive.

  3. May 2, 2012

    I’ve always been wondering why the PR of static sites is more than my CMS Sites.
    Now I know why. This has been really helpful
    Thanks a lot.

    • Kathy Alice permalink*
      May 7, 2012

      Yes, intra-domain duplicate content can really hurt if you are a bigger site. I’ve fixed sites which had about 1000-2000 true unique pages (but had something like 5000 indexed) with just the canonical tag and we saw a 20% gain in traffic.

  4. Niklas permalink
    December 10, 2012

    Hello i have a question. We have a product site about spices and we have some recipes under the products. then a new portfolio category with the same recipes and we have them in the blog. I tried to argue about the dupe content but the owner didn’t want to listen because she wanted it on all places. What do you think?

    • Kathy Alice permalink*
      January 26, 2013

      It’s fine to have the same content in multiple places but just give the search engines one place to find it and noindex the rest.

  5. May 1, 2014

    Thanks for the tips.

    Having a big issue with duplication at the moment on a magento website

    Thanks
    Mike

    • Kathy Alice permalink*
      May 7, 2014

      eCommerce sites often have duplication caused by faceted navigation . Good Luck!

  6. virender yadav permalink
    September 8, 2014

    Dear Ms Kathy please help me i have duplicate urls in my website http://www.jobsnexams.com which is a self hosted wordpress site and i want to remove from its database how can i do this please suggest me. I’ll be very grateful to you.

    • Kathy Alice permalink*
      September 16, 2014

      Hey Virender – I need a bit more information before making a recommendation: there’s a lot of information in the article to get you started.

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