SEO Test: Sending Mixed-Signals to Google

 
 

This is an SEO experiment designed to ascertain whether it is possible to confuse Google into noindexing your pages with combined use of rel=”canonical” and “noindex”.

Read on to find out how we intend to do it and how you can help the experiment.

noindex

Note: Full credit for this experiment goes to Giacomo Pelagatti (SearchBrain) who first felt the crack in the matrix and would not stop asking question until he got his answers.

The Hack Mechanism

Google relies on rel=”canonical” to merge all substantially similar URLs into a single canonical version of the page. If some of your canonicalised pages use noindex you could be sending a mixed signal to Google and there is a possibility they may choose to noindex the canonical version of the page as well. We don’t know the exact conditions under which this is likely to happen, but the general recommendation is to reduce noise and ensure you’re sending a clean message to Google to prevent any undesired effects.

Background

In August, 2012 John Mueller recommended not to use noindex with rel=”canonical”:

“You mentioned the noindex… Generally speaking, I would avoid the situation where you’re using a rel=canonical together with the noindex, because it can happen that we take the noindex and also apply it to the canonical [URL], because technically the rel=canonical is meant to be used on URLs that are equivalent and if we see the noindex on one URL and we think “Oh, this is equivalent to the other URL” then we might apply the noindex to the other URL as well. So, really try to stick to things like redirects from one version to the other or the rel=canonical, for example.”

Giacomo was intrigued by this and sought further clarification on that and similar issues. Final clarification was finally given this year by John Mueller in the following post:

“…you should avoid ever sending mixed signals. If you want something specific done, you should make it as clear as possible. If you’re saying that these URLs are equivalent, but noindex one and try to have the other one indexed, then that will be unclear — always be as clear as possible.”

 And finally:

“When we have a group of URLs where we can choose one canonical, it’s pretty much the case that we assume that these URLs are equivalent — so apart from “optics,” it wouldn’t matter which of the URLs we pick as the canonical. With that in mind, if we have a mixed set of “index” and “noindex” URLs in there, then it’s not completely clear what we should do with that set of URLs: index a representative, or not? or perhaps we should assume that they are not, after all, URLs that can be grouped together? If you, as the webmaster, have a strong opinion on that, it’s always better if you take the decision into your hands and give a clear signal regarding what you want us to do with your URLs.”

The Experiment

Toni Anicic joined the discussion and suggested I run a test. Naturally I could not resist the urge, but unlike last time, I decided that my own domain should be the victim of the attack.

To help with the experiment do the following:

  1. Rip this page: http://dejanseo.com.au/link-disavow-statistics/ (it will contain canonical back to my page)
  2. Add noindex to it <META NAME=”ROBOTS” CONTENT=”NOINDEX“>
  3. Upload it anywhere on the web and let us know in the comments.
  4. Periodically check this search result to see if I was kicked out.

 

Dan Petrovic is a well-known Australian SEO and a managing director of Dejan SEO. He has published numerous research articles in the field of search engine optimisation and online marketing. Dan's work is highly regarded by the world-wide SEO community and featured on some of the most reputable websites in the industry. Questions? Here's Dan's contact email.

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18 Responses to “SEO Test: Sending Mixed-Signals to Google”

  1. Very interesting, I will check back to see if it works. I see the logic behind it, but I would be surprised if it works.

     
    • Trevor Stolber
  2. Same here, I hope we fail.

     
    • Dejan SEO
  3. Testers may want to double check the canonical link after ripping that test page because it might be treated relatively.

    http://www.khemistry.org/noindextest.html

     
    • GeorgeZhu
  4. Nice reading, share the results once you get’em. Noticed a typo in 4th paragraph, “could be sending could send”.

     
  5. My clone is up; let’s see what happens: http://www.giacomopelagatti.it/link-disavow-statistics/

    Just a note: since the original page includes a , I would recommend editing that (replacing “noodp,noydir” with “noindex”) instead of adding a new meta tag.

     
    • Giacomo Pelagatti
  6. Hi Dan, I have setup the following URL – http://www.promomasters.at/partner/link-disavow-statistics.html – but I think that it might be important if the canonical or the nowollow is set 1st?!?! I have set the nofollow after the canonical

     
    • Michael Kohlfürst
  7. Its likely Google will index the page but with a basic meta title and no description. Like a no indexed page that has links pointing to it. $20 bet!

     
  8. Mine is up at http://www.highonseo.com/disavow-link-stats.html and a blog post that is also no-indexed so Google sees the link as part of my “regular” posting at http://www.highonseo.com/2013/02/how-to-noindex-your-competitors/ I’m going to push a few links into this site as well to see if that helps.

     
    • highonseo
  9. Thanks!

     
    • Dejan SEO
  10. Thanks George!

     
    • Dejan SEO
  11. Thanks Giacomo!

     
    • Dejan SEO
  12. Thanks Michael, will see what happens. Hopefully nothing :)

     
    • Dejan SEO
  13. Hi Dan, in Austria I see “Link Disavow Tool Statistics” including your Author Tag. 6 Days ago from dejanseo.com.au (Austria is not Australia ;-) )

     
    • Michael Kohlfürst
  14. A week has passed; nothing happened. Can I take my clone down?

     
    • Giacomo Pelagatti
  15. My clone is now 410 (Gone).

     
    • Giacomo Pelagatti
  16. Hi Dan, the results are still the same after +14 days. Will you let us know when to stop the test? Thanks, Michael

     
    • Michael Kohlfürst
  17. I will now delete the file as there has been no more discussuin about this test.Have a great time in California, Michael the PromoMaster

     
    • Michael Kohlfürst
  18. Nice experiment, its like knowing if google will crack. I really like the idea, the risk and the guts to perform this experiment made me think that i also want to perform this kind of experiment. Well, lets hope that this experiment would fail – as to what we all wanted. Ill wait for the update of this.

     
    • Spook SEO

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