Multiple URLs serving the same content? Canonicalize 'em!

Multiple URLs serving the same content? Canonicalize 'em!

17.Nov.2021

Conventional SEO wisdom says that no two URLs can serve the same content, but it's common for this assumption to be proven incorrect when dealing with dynamically generated content.

 

If you've got two URLs that serve very similar content, consider canonicalizing them, using either a 301 redirect (if there's no real reason to maintain the duplicate) or a rel=canonical (if you want to maintain slightly different versions for some visitors, e.g. a printer-friendly page).

 

The most common case of duplicate URLs is with dynamically generated content, when there are at least two URLs that are generated based on the same content.

 

Some website owners have tackled this problem by simply using a 301 redirect to address the less significant URL, so let's take a look at some of the benefits of doing so:

 

- The value of link equity passes from one page to another;

 

- It prevents Google asking you to "Please remove all versions of this page from your index" as happened to Moz's own Rand Fishkin some years ago;

 

- It avoids possible issues with duplicate title tags and metas.

 

That being said, there are a few cases where it makes sense to keep more than one version of a page:

 

- If you have a printer-friendly version of the page, it makes sense to keep that linked separately.

 

- Perhaps you have two different versions of an article for different audiences (one for kids and one with adult language). Google is aware of some situations like this where content should be indexed but not fully displayed on the page.

 

However, if there is a slight difference in content, the rel=canonical attribute may be a better fit.

From John Mueller at Google:

 

"The canonical link element is meant to avoid indexing of duplicate pages and consolidate indexing of basically similar pages."

So if you have two URLs that serve very similar content, consider canonicalizing them, using either a 301 redirect (if there's no real reason to maintain the duplicate) or rel=canonical (if you want to maintain slightly different versions for some visitors, e.g. a printer-friendly page).

"When choosing canonical links, keep in mind that search engines may apply a value to the canonical version of your site, which might affect how your pages are displayed in search results."

Note that John's wording here is a bit confusing, as he says " may apply a value", but the 301 redirect is considered an instruction for search engines , not an additional ranking factor.

"Please note that some sites intentionally choose to use rel=canonical on every page of the site to explicitly indicate which version is canonical."

In cases where there is a more significant reason why two different URLs should exist, find the page with the higher value and add a rel=canonical attribute pointing back to it.

"If you decide that using outbound links from your duplicate content can help users reach your preferred version of the content, you can use rel=canonical."

John goes on to say that if you want to link to another version of the page from your duplicate version, you can consider using a rel=canonical.

"If your website is affected by this issue, we recommend removing all "View X developed by Y" links from the affected pages and using rel=canonical where appropriate to point to the preferred version of those pages."

If you're noticing that Google is crawling many URLs on your site where it's difficult for you to determine which is the more important, consider removing the duplicates by either 301-redirecting or using a canonical link.

John makes it clear that if you have a lot of duplicates, Google may balance their value by crawling fewer pages. If this happens, find the page with the most value and use a 301 redirect or rel=canonical link to send both search engines and visitors to that page.

John concludes his video with a great tip: "If there's a way for you to tell us which version is preferred, it can help refine our crawling and improve your site's performance in search results."

John finished his post by making clear that if you have a way to communicate with Google about which URL is more important, they will take that into account when crawling your website.

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