There's been a long-standing controversy about the usage of subfolders compared to subdomains when attempting to structure a website, and which one is better for SEO.
According to John Mueller, a Google Webmaster Patterns Researcher, Google is treating subfolders and subdomains the same. Although Google might use the same ranking factors to index a subdomain as it does to index a subfolder, when deciding for yourself, there is some reasoning to take into account.
What is a subdomain?
Although Google may use the same ranking factors to index a subdomain as it does to index a subfolder, there is some justification to take into account when deciding for yourself. For instance:
In this example, the subdomain is 'shop', the primary domain is 'your website' and the top level domain (TLD) is '.com'. As your subdomain, you can use any email, but you want to make sure it's simple to type and remember.
This link uses a series of subfolders: ‘/blog/blog-title’.
Importance of subdomain or subfolder in SEO
To determine the indexability of a Web page, Google uses more than 200 things. Just one of them is the URL structure.
Keep your horses up if you read this and decide you want to make the move. It could lead to loads of 301 or 302 redirects to make unprepared and mass modifications to URL structures. Lots of broken internal ties may be caused. That could lead to the dreaded 404 mistakes. On-page speed or structured data could be lost.
How to decide when a subfolder or subdomain should be used
Many SEO specialists would inform you that for most websites, subfolders are the wiser option.
This way, by modifying your subfolder paths (i.e. '/blog' or '/pricing' etc.), you can house all of your URLs under a single domain name and maintain a simple, logical structure. This practise preserves the authority of ties and helps create the overall authority of the domain. These are primary variables that are searched for by search engines.
But, let 's say, Microsoft is you. Multiple stuff are you talking about. To answer questions, you may set up a dedicated subdomain, and a dedicated subdomain to manage all your events.
Yeah, these sub-domains are under the Microsoft brand umbrella, but they're neatly isolated from the main site. And chances are, as if it were its own website, Microsoft has a dedicated team to handle each individual subdomain.
Subdomain over subfolder
While all of their subdomains will be connected by certain external connexions, most may only connect to one or two at most.
Each subdomain acts essentially within the overall company as a separate "business."
They can be very good in achieving great rankings when subdomains are used in this way. Each subdomain is autonomous and may or may not be affiliated with the main entity.
In deciding to use a subdomain over a subfolder, these connexions are very significant and are the biggest factor.
If your subdomain content functions as a separate entity and gets its own link value, then your subdomain content is good and, in some cases, even preferable.
Subfolder over subdomain
The subfolder solution is much less work, unless there is a good need to separate business units.
You're more likely to maintain it because it's less effort, which would possibly translate into better rankings.
In a nutshell ...
The overall subject of your website is something Google needs to learn. Using subdomains if you've got two different items that speak about two separate things. That way, you can break your voice tones and help Google understand your website's intent better. Likewise, if you have anything like a dedicated support site (like Microsoft does), segregate it with a subdomain and treat it like its own website.
Use a subfolder if you have sites that are part of your main website, such as a pricing page, a blog or a about us page.
In 2020, subdomains vs subfolders
The discussion on subdomain vs subfolder is still ongoing. There is, truthfully, no such thing as a correct answer. Based on experience and experimentation, there is only best practise.
Then, to your best judgement, we encourage you. Make sure it is well thought out if you plan to make a switch. Only one SEO element is URLs. Next, remember the rest of the website.