While helping a company that was heavily impacted by several algorithm updates in the fall of 2023, I started by scanning GSC reports to get a feel for the situation. And when digging into the inbound links report, I started noticing something funny across a number of links. There were some relatively powerful referring domains in the list, but when checking the urls receiving those links, the target url was different. In other words, the url receiving the link was actually via a separate url… That can happen, but what I discovered was a little different. The target urls were from another site. Therefore, inbound links counted for my client’s website were actually from a third-party domain.

Dan Petrovic called this “link inversion” back in 2018. I have also seen this before a number of times over the years and I quickly had a feeling what was going on. This can happen when Google canonicalizes urls from other sites to a url on your own site. That’s typically when Google sees the same content across multiple domains and selects a single canonical url. And the links pointing to those third-party urls are now being transferred to the canonical url (which may or may not be on your site).

For some sites, you might be very familiar with those third-party urls containing the same content (like other company-owned sites that are publishing duplicate articles or pages). But for some other sites, they might have no connection to your site at all. For example, my client had no idea this was happening and what the effect of “shifting signals” could be.

To make matters even more complex, since this often happens when there’s duplicate content across sites, Google can always reverse its decision about which url is the canonical. I’ve seen this happen in the past and all signals suddenly point at a third-party url versus your own (and obviously the third-party url will rank in the SERPs). If you don’t know this is happening, it can definitely cause some confusion with rankings, impressions, and clicks to those urls.

Again, this is not new, but I wanted to post a reminder about how this works since it can be a tricky situation to hunt down. I’ll cover more about this below.

Finding The Hard Evidence: Visit The Links Report In GSC
Based on what I explained above, you might think you can run to the URL Inspection Tool in GSC and find this information. Well, that depends on which end of the canonical decision you are on… The URL Inspection Tool will only reveal you when your urls are being canonicalized to other urls (which could include urls on third-party domains). But if third-party urls are being canonicalized to your urls, then you will not see that when inspecting the urls in GSC.

But, there are other ways to track this down. One way to see this in action is to check your inbound links in GSC (like I mentioned earlier). When clicking into a target url in the reporting (the url receiving a link on your site), you can see if the target url Google is reporting is different. And if it is different, it could be a third-party url (on another domain). And if that’s the case, then it’s telling you that your url is receiving the inbound links versus the third-party url. So signals, including PageRank, are being applied to your url.

Here is an example of what that looks like (I changed the domains and urls to blind the sites involved):

Raining on the (SEO) Parade: Manual and Incomplete.
But hold your applause. There are serious limitations to using this approach… The inbound links reporting in GSC does not provide a comprehensive list of links, especially for sites with many links. There’s also no API for the inbound links reporting, so this process is manual and incomplete. And those are two horrible words for any SEO to hear. 🙂

If you bulk export links from GSC (top-level), you can get up to 100K links, but you don’t have target url information, canonical information, etc. You must drill into referring domains and urls in the links reporting to get that information (which is an extremely manual process).

Trouble In Paradise: The Canonical Role Can Flip
Remember, the “shifting signals” situation can typically happen with urls containing the same content (duplicates), which might also be PDFs that are duplicates across sites. For example, maybe multiple sites host the same exact PDF and Google needs to decide which one to rank. Depending on several factors, Google can change the canonical url when it believes it should. And then signals, including PageRank, will now get passed to the third-party url. Hence why I titled this post, “Shifting Signals”.

You can learn more about how Google selects a canonical by watching this great video from the Google Webmaster Conference in 2019. I was in the audience and loved this presentation from Google’s Allan Scott:

And when your url is suddenly not the canonical one, your url will not rank anymore and all signals will be passed to the canonical url (which is now on a third-party site). Again, I know this isn’t a widespread problem across many sites, but if this is happening with urls on your own site, you should know about it. For example, the client I mentioned earlier has thousands of urls where this is happening based on their setup.

Here is an example of the canonical switching on my client’s site. The page literally disappears from the SERPs when the canonical switches and then returns when the canonical switches back again:

The Flow of Signals Through Your Site:
And remember, those urls on your site were receiving inbound links via third-party urls, and then your urls are passing signals downstream to other urls on your site (if you provide internal links from those urls). Those signals essentially get cut off when your urls are not selected as the canonical anymore.

And depending on how many urls this is happening to across a site, it can potentially cause problems rankings-wise for other urls being linked to from the urls losing the canonical status. And then there are site-level algorithms that Google is using, which could very well be using link signals to some degree. So again, if you have many urls with this happening, it could be impacting more than just the urls losing their canonical status. It could impact other urls that are downstream on your site.

Regarding canonicals switching on and off, I was helping a health and medical site several years ago with a lot of content that was licensed from a third-party resource. I watched the site surge and drop over time based on which site Google saw as the canonical (url-wise). If my client’s site was selected, they ranked through the roof for extremely competitive health and medical queries. If the canonical changed to another site with the same licensed content, then boom, they simply didn’t rank as those urls were canonicalized, not ranking, and not receiving the inbound links that the cluster built over time.

I warned my client about this many times, but it wasn’t a priority for them based on their business model. It was simply fascinating to watch over time (and especially during major algorithm updates when big changes would often happen on this front). The entire directory holding that content was exhibiting yo-yo trending when canonical urls switched.

Summary: Understanding the “shifting” of signals, links, and rankings.
Shifting signals can be sneaky and hard to uncover, but it could be happening for duplicate content on your site. And you might be benefitting from the shift, or not, depending on how Google’s systems are viewing the canonical situation. If you have a lot of content that could fall into this category, I recommend trying your best to uncover what’s happening and then form a plan for addressing that (if you can). At a minimum, it could at least help you understand why your site is appearing, or disappearing, for certain queries over time. In other words, try to understand the “shift”.

GG