Mind Your Canonical Tags – Latency Issues

01 Jul Mind Your Canonical Tags – Latency Issues

Introduction & Backstory

We had a site recently that was built to have a number of dynamically generated pages based on geographic locations. These were setup using a URL rewriting tool for “pretty URLs” and as such we wanted to make sure that Google always attributes the page to the nicer “pretty URLs” instead of the possible alternate URLs that include QueryString variables.

For this specific case, Google pioneered the “Canonical Tag” which is a flavor of the LINK tag that looks like this:

<link rel=“canonical” href=“http://dbdnet.com/” />

Where the “href” attribute is the desired URL for the page being looked at.

With this tag Google views it as a recommendation from the web developer as to which page should get the link equity from external links to a page even though the URL may be different. This also allows them to understand that these pages aren’t meant to be purposefull mirror pages but rather two URLs that simply end up displaying the same content, and the Canonical Tag shows Google which version of the URL you prefer.

So two URLs like these:

  1. http://dbdnet.com/test/indiana/
  2. http://dbdnet.com/test/index.htm?state=indiana

These could display the exact same content. Through the use of the Canonical tag, you can tell Google that you prefer that it recognize #1 as the true URL.

Another example could be if your site uses QueryStrings to keep track of user activity or marketing campaigns such as this:

  1. http://dbdnet.com/marketing-campaign/
  2. http://dbdnet.com/marketing-campaign/?user=XYZ

Google would normally index both pages as unique URLs, and then the two would confuse Google as to which page should be displayed in the search results. Using a Canonical tag allows us to tell them that #1 is all they need to remember.

Latency Issues with Canonical Tags

So to the point of this post… We had an error in the dynamically generated Canonical tags when the pages first launched that pointed Google to a level higher in the site heirarchy than it should have. So Google ended up on our geographic pages but then attributed all the links and information about that page elsewhere.

We caught the issue rather quickly and corrected the code that generated the tags. Then we waited… And waited… Generally it takes a week or less for Google to index new pages. We waited nearly three to see if Google would re-index our pages. Google was not coming back around for these.

We finally decided we couldn’t wait any long and through collaborating with our SEO friends at Performics the call was made to change our URLs slightly so that Google would view them as entirely new pages. We also decided to NOT put in 301 redirects from the old version to the new version as to have no chance that Google would pass on any bad karma from the old pages.

As soon as we made the new URL change, it was right at a week when Google started indexing those geographic pages under the new URLs. Just as expected.
Lesson Learned

Even though Google talks lightly about Canonical tags as “recommendations” that they may or may not listen to… If their algorithm decides to record the recommendation, then it doesn’t want to let it go.

Just watch your Canonicals closely and make sure they are the EXACT URL that you want them to be.

Brandon Luhring