RACHEL COSTELLO: I think that a lot of people
see canonicalization as kind of topical grouping, which
kind of isn't right at all.
They need to, the pages need to be either identical or near.
MARTIN SPLITT: Near identical, exactly.
RACHEL COSTELLO: Yeah.
MARTIN SPLITT: Yeah That's what it boils down to.
Canonicalization is about duplication management.
So basically, you want to remove duplication,
so that we don't have to crawl things multiple times
and we don't have to render and index things multiple times.
And we also do not serve them all the time,
like the same things basically in three different URLs.
That's not good search results really, right?
[MUSIC PLAYING]
Hello, everybody, and welcome to another episode
of "SEO Mythbusting."
With me today is Rachel Costello.
You are a DeepCrawl Technical SEO and Content Manager.
So what is it that you're doing every day?
RACHEL COSTELLO: So I basically, well, I
used to be a technical SEO myself,
and now I've moved into more of the content production
side of things.
So writing white papers, articles,
to educate the wider dev community, digital marketing
community, about technical SEO and the impact it has.
MARTIN SPLITT: Awesome.
That's really interesting.
So you're seeing a bunch of misconceptions and confusions
and stuff.
And we picked an interesting topic, didn't we?
RACHEL COSTELLO: We did.
MARTIN SPLITT: What's the topic that you
want to talk about today?
RACHEL COSTELLO: It's all about canonicalization.
MARTIN SPLITT: Ooh.
All right.
So what are the top myths and misconceptions
that the community is dealing with?
RACHEL COSTELLO: So I think the first thing is that people
think it is a directive.
You set a canonical tag.
It's going to be accepted.
Another one, yeah exactly.
Another one is that they kind of use it like a redirect.
So if you have a product page that goes out of stock,
you add a canonical to that category page, which
doesn't really work that way.
Because I've heard that the content needs to ideally
be identical, if not very similar.
MARTIN SPLITT: Yeah.
RACHEL COSTELLO: So lots of things like that.
MARTIN SPLITT: Oh, interesting.
All right, let's start with the idea
that it is a directive, because it's not.
RACHEL COSTELLO: No.
MARTIN SPLITT: No.
It is a signal for us, right?
So when we talk about canonicalization,
we're talking about detecting content or the same content
or a very similar content that exists on different addresses
and the different URLs, right?
So we can do many different things to basically
identify these things, right?
We can just crawl multiple pages and see like, oh, this
is actually the same content.
We can also probably see if the same links
and like the same kind of context is used.
But also, we can use the canonical tag, right?
It's a signal.
We're using many different signals
to figure out if something is the same content or not.
And canonicalization with a canonical tag
is just one of them.
So putting a canonical tag on pages that are not the same
is not going to work.
Putting a canonical tag on each of the pages that
are exactly the same is also not going to work.
It is a signal.
It helps us identify what we want to canonicalize,
but it doesn't say you have to use this.
That's a big one, I think.
And you're right.
And you should not use it as a redirection either.
It's not a redirect.
RACHEL COSTELLO: I think people just want to group link equity
wherever they can, and it's maybe
a bit of a desperate act to try and keep all of their link
equity in one place.
MARTIN SPLITT: It is, it is.
Again, like canonicalization makes sense
if you cross post the same content
on different, I don't know, platforms,
or different channels in slightly different locations
for whatever reason you're doing that.
That's where canonicalization comes in.
But if you are having something that goes out of stock,
you should either redirect it to something similar that
makes sense for the user at that point, or you can just tell us,
this is a 404 for the moment and might come back.
But do not just think that you can,
no, it's not the same as a redirection.
Also, you're wasting crawl budget that way.
Because we are just not understanding
like, oh, so you're saying this is the same as the other page,
but it clearly is not.
So we're just going to continue doing this.
But if you have two pages that are identical
and you're not canonicalization or you're not canonicalizing
them the way that it makes sense,
then we kind of have to look into both as well.
And sometimes we get these like flipping canonicals.
Yeah.
What are the typical problems that you're
seeing that people are having besides these misconceptions?
Like, what are people doing with them you think makes no sense?
RACHEL COSTELLO: So I think people are just not quite sure.
We've been trying to piece together
what these different signals are that play into [? effects. ?]
You've got redirect, site maps, backlinks and things like that.
I think people are trying to weigh up
how many of these signals they should add.
Maybe they're kind of doing it like a mass equation.
Like if I do these two things, then
this will mean that Google picks my canonical tag that I want.
But it would just be interesting.
I'm always interested to know more about how
the signals are weighted, which ones are
more preferential to others.
Because sometimes I see that maybe,
this is just my theory, that maybe Google
puts more weighting to signals that
are more likely to have been implemented
by human rather than maybe an auto-generated setting.
I don't know if that has any.
MARTIN SPLITT: Well, duplication and deduplication
is actually done without much human interaction.
So this is all automated signals.
But we do like content fingerprinting.
We look at things like, what is the gist of it
really, what are the, what's the information here,
how does this relate to the site structure, what
does it say in the site map.
So we're looking at a bunch of different factors,
but they're mostly technical factors.
RACHEL COSTELLO: OK.
MARTIN SPLITT: Yeah.
And we are basically scoring them on an ongoing basis.
So it's not that we're like determining at once
and then just stick to it.
We are always looking at the fresh content
that we got from crawl, and then have a look at, does
this change, is it changed, is it now very close
to what it has been before.
Now maybe something that has been in duplication
is no longer a duplicate, because it
has changed its contents.
So that is absolutely possible, right?
But sometimes, especially when pretty much everything
is showing up in the same URL structure
and it's maybe like different language
versions of the same thing, but it is the same content,
then we might end up with a scoring that is very similar.
So we have both versions.
And let's say like one 0.49 and one
is 0.51 of what we think is a duplication of the other,
then it's really hard to pick which
one will be the canonical.
And that can change, right?
A change in, I don't know, how we crawl things
or how the crawler has fetch data
and how it has been touching the other pages
beforehand might influence us to have like a tiny little bit
of a jump in these two numbers.
And then the other one is the canonical.
So make sure that you're trying to give us as clear a signal as
possible and not confuse the algorithms that are working
with figuring out which one is the duplication of which
other thing.
Because if we are having two equal pieces of content,
then how do we know which one we should pick?
RACHEL COSTELLO: Exactly.
And you don't want Google to be in that position
where they feel like they have to pick for you
or Google bot feels like it has to pick for you.
MARTIN SPLITT: And it makes everything
more complicated on your side as well.
RACHEL COSTELLO: Yeah.
MARTIN SPLITT: Especially if you're using things
like search console, right?
We are, we're gathering data and showing you data
based on the canonical.
So if it starts flapping between two URLs,
then that's going to look really weird.
RACHEL COSTELLO: Mm-hmm.
MARTIN SPLITT: So anything else that you
would say is unclear about it or is there
something that makes your life really hard when it comes
to kind of canonicalization?
RACHEL COSTELLO: I think it's figuring out
that certain thresholds you need to get
to override Google's decision on what is the preferred URL.
Because we can align all of our signals on site.
I saw that John Mueller on the Ask Google Webmaster video
about canonicalization, he said that there's two aspects.
You've got kind of the on site signals,
but you've also got what Google thinks that the user would most
like to have a look at.
MARTIN SPLITT: That's true, yeah.
RACHEL COSTELLO: Yeah.
MARTIN SPLITT: That depends on a bunch of different things.
So for instance, we might canonicalize one language
version over the other.
If you were telling us that all of them
are canonical at the same time and they have pretty much
the same content, especially if it's in the same language,
just for different countries, then we
might show the version to the searcher
that the searcher is in the country of.
So if we have a DE version and an AT version,
of the German version and an Austrian version,
that are pretty much the same.
They use the same currency.
That might have even the same price, if you're unlucky.
We might show different URLs to searchers,
depending on where they are from.
It makes more sense for a customer in Austria
to see the Austrian version of the website
rather than the German one, even though the German one is
the canonical.
So that might be a little confusing and misleading.
RACHEL COSTELLO: Mm-hmm.
MARTIN SPLITT: Any other questions from your side?
RACHEL COSTELLO: Yeah, so there was one question I had in that.
So if Google accepts the canonical tag on a page,
that it will ignore any unique content on that page.
But then that's interesting, because surely, the pages
have to be identical in the first place.
This is something I've heard.
If there's any unique content on the canonicalized page,
it'll be ignored.
So how would that work?
Would the canonical tag not be accepted then,
because they're slightly different pages?
MARTIN SPLITT: So that depends on how different
the unique content is.
If you have mostly the same content
and then maybe have like one sentence
that is slightly different, then we
might still think that it's pretty much the same thing.
And then we would not see the unique content necessarily
if we think that it's just a copy of another page that
is canonical.
If this page has the canonical, then we
would probably see the unique content there as well,
because it's the page that we picked.
However, if the content is completely different
or different enough for the algorithms
to decide that this is not a duplication,
then the canonical is pointless.
RACHEL COSTELLO: Mm-hmm.
MARTIN SPLITT: Unless there's another page that happens,
or another URL that happens to point to the exact same page.
Then it becomes interesting again,
because then we have two different pointers
to the same thing.
And we get that oftentimes that people
are like linking [? to ?] pages and accidentally
have like some, I don't know, some URL parameter that
basically gets ignored or doesn't actually matter,
or there's like a slightly difference in the way
that the URL looks like.
Maybe you have like a slash de, something something,
and then like slash de, something something question
mark, cache equals falls or something
like that, that doesn't really matter.
Then we might canonicalize one of these pages, and probably
the one that does not have parameters and stuff.
That also is debatable.
It might also happen that we canonicalize something
with parameters.
But that way, you're again making it harder
for us to pick a canonical, because if you're not
saying like, oh, this is specifically
the canonical we want, then it's back to guesswork.
RACHEL COSTELLO: Mm-hmm.
And I think that's the problem.
People are just trying to group pages
topically maybe with canonicalization,
but that's not how it works.
MARTIN SPLITT: That's not how it works, no.
RACHEL COSTELLO: Thank you for confirming that.
MARTIN SPLITT: Canonical tags and canonicalization
is about reducing duplication.
RACHEL COSTELLO: Yes.
MARTIN SPLITT: That's what it is for.
RACHEL COSTELLO: Exactly
MARTIN SPLITT: Awesome.
Rachel, thank you so much for being here and talking
a little bit about canonicalization with me.
And I think that was useful.
And I hope you enjoyed it.
Have a good time.
Bye bye.
[MUSIC PLAYING]
Hey, everyone.
I hope you liked the previous episode.
Next episode, me and Glenn are going
to discuss site moves, right?
GLENN: Site moves, domain name changes, URL migrations
and more.
MARTIN SPLITT: So stay tuned and check it out.