Introduction
Ever Googled a subject and found two, three, or more versions of unrelated websites appearing? The URLs might have had those weird parameters like ?ref=, /index.html, or /page=2? How wonderful canonical URLs, eh? Essentially, they blackleg the SEO referee to decide which page shall be treated as the “main one” amidst duplicate pages.
For businesses and marketers, canonical tags allow search engines to not get confused, to combine ranking signals, and to prevent your site’s authority from being split among duplicate content. So if you’ve ever been wondering why stuff just does not rank high enough for you, I’ll tell you: canonicalization can be.
In layman’s terms: what is a canonical URL?
A canonical URL is a URL an individual considers to be the search engine’s perceived original. By tooling a canonical tag into a web page’s HTML, with rel= “canonical” in the attribute, one increases the count of canonical URLs.
In fact, one would say that searching for it on Google implies: “Let’s consider this the main piece of content. Ignore the other versions.”
Let us say these URLs offer a page supposedly:
example.com/page/
example.com/page?utm_source=twitter
www.example.com/page
A canonicalized URL can set all URLs to just one of them, say https://example.com/page/.
Why does SEO care about canonical URLs?
Here are canonicalization considerations from an SEO perspective:
Prevent duplicate content penalties – Search engines do not like being shown the same content at separate locations. Canonicalizing solves that.
Consolidate link equity – The more links an entity has, the stronger it becomes. When split, the strength diminishes. Carrying out canonicalization sends all the link juice to the URL of choice.
Better indexing – Search engines then crawl well, index well, and rank appropriately.
Track performance much better – Analytics get so much simpler when all traffic is thrown into one primary page.
As Aaron Greene, SEO specialist, once said, ‘Canonical tags are like traffic police for your site. They direct all signals to the right page and prevent SEO jams.’
How do canonical URLs eliminate duplicate content problems?
Duplicate content does not necessarily mean that a copy has been done against you. Sometimes it can be due to situations such as:
Session IDs are implanted in URLs.
UTM tracking parameters may appear.
Printer-friendly versions may exist for a site.
HTTP and HTTPS.
WWW versus Non-WWW.
In the absence of canonicalization tags, different versions of a page may get indexed separately by search engines; thus, ranking power gets divided. Via canonicalization, you are basically telling Google which copy should be treated as the “preferable” one.
Ecommerce SEO is one argument in itself, where duplicate pages get generated for product pages (color variations, sorting options, filters).”
When would you use a canonical? When for a 301 redirect?
Commonly confused subject.
Into the mind:
1. A duplicate page on a site is a crime, and canonical tags are one defense.
2. When pages are duplicates and you would rather have one, that’s when you redirect, etc.
3. Every time you think about canonical tags, ask yourself whether you should use a redirect instead.
The canonical tag finds application in cases when duplicate pages exist just for users, but one wants to communicate to Google the “main” one. The examples are product variations and tracking links.
A 301 redirect, of course: When a duplicate page should not exist at all, and all traffic has to be redirected permanently toward one. Example: HTTP to HTTPS.
One universal guideline: If there is a page which you want to be “alive” out there in front of the users, then go canonical on it. Everything else just gets redirected.
What are some common mistakes regarding canonical URLs?
Things we should watch out for (competitor sites will probably throw in some):
Having everything point to the homepage (bad idea-good way to confuse Google).
Using relative URLs instead of specifying them fully. Always specify the full URL.
Forgetting self-referential canonicals (each page should point to itself, unless it is a duplicate).
Declaring multiple canonicals (over which Google can simply choose to ignore).
Not being able to update canonical tags in migrations or redesigns.
What do canonical URLs fix for eCommerce SEO?
Ecommerce domains are the top duplicators. Think category filters, product variations, and infinite tracking codes. What can canonicals do for you?
They give ranking power to multiple product pages.
Make the original product rank instead of some random variant.
Prevent index bloat (basically to stop Google from wasting its crawl budget on duplicate product URLs).
Therefore, canonicalization in an online store must be on the same priority list as site speed or mobile-friendliness.
FAQ
Q: Do canonical tags really transfer link equity?
A: While most signals, such as backlinks, tend to consolidate on the canonical, there is never a guarantee of such.
Q: Can cross-domain canonicalization be applied?
A: It can be, but only if the content is an exact match. Be wary.
Q: Should every site have a canonical tag?
A: Yes, even on the canonical URL pointing to itself. It just confused search engines in scenarios where duplicates might have existed accidentally.
Q: Could I view my canonical tag as a redirect?
A: No, they are not the same. Canonicals serve the indexing side; redirects are against actual user traffic.
Q: Would you suggest that canonicals be a 100% guarantee that Google will follow their preference?
A: Not necessarily; if the contents are inconsistent, Google may indeed go its way.
Conclusion
Sufficient technical jargon about the canonical URL; WORST SEO problem in an in-site setup remains one where you, as the website owner, have left it ambiguous to search engines as to what the real document is. By doing so you eliminate duplication, build backlink authority for one page, and essentially give your pages their best fighting chance to rank.
If a canonical audit of your Web presence has not been carried out, well, now is the right moment. One single tweak can bring so much SEO value.
What do you think about canonicals? Do drop a line in the comments; I would love to connect with you!