The official word, according to this video from Google, is that they treat subdomains and subfolders equally. This is absolutely true. Google crawls, indexes, and ranks subfolders or subdomains exactly the same way. You have just as much ability to get a subdomain ranked as you do to get a subfolder ranked.
Why SEO Pros Don’t Agree
So why do so many SEO pros disagree on this?
It’s all about the effort involved.
While you can get either ranked, the effort it takes to get a subdomain to rank is often much higher.
Let’s start with a basic explanation of how domains work:
- A top-level domain (example.com) is purchased from a registrar.
- The registrar provides the right to the domain.
- To host a website on the domain, you have to pay a web hosting company (or be your own host) to connect that domain to an FTP server, which holds the content you want shown on that website.
This is an oversimplified explanation, but you’ll soon see why it matters.
Once you connect that domain to content on a server, you’ll be presented with a choice:
- Do you want the content to be on a subdomain, (e.g., www.example.com)?
- Or do you want it to be on the top-level domain, (e.g., example.com)?
If you choose the former, which most sites do, your content is already on a subdomain.
Because some sites choose to place dramatically different content on subdomains, Google treats each separate subdomain as its own entity.
Why Choose a Subdomain Over a Subfolder?
Disney is a great example.
They have cars.disney.com, videos.disney.com, disneyparks.disney.com, princess.disney.com… Each one serves a very different purpose.
Disney markets each subdomain separately, obtaining relevant links to each entity separately.
While some external links might link to all of their subdomains, most will only link to one or at most two.
Each subdomain basically functions as a separate “business” within the overall corporation.
When subdomains are used in this way, they can be very successful for obtaining great rankings. Each subdomain stands on its own and may or may not be linked to from the main entity.
These links become very important and are the biggest factor in choosing to use a subdomain over a subfolder.
If your content on the subdomain will function as a separate entity and obtain its own link value, then it’s fine and in some cases even preferable to have your content on subdomains.
After all, links to cars.disney.com can all be about the “Cars” movie franchise, instead of diluting the topical focus of the site into theme parks, entertainment media, and shopping, just to name a few.
Why Choose a Subfolder Over a Subdomain?
But most businesses aren’t as faceted as Disney.
Most sites focus on one or two main topics.
An attorney site is a good example.
Suppose the site focuses on family, personal injury, and liability law.
While the site could break these areas into individual subdomains – familylaw.site.com, for example, and Google will treat this the same as site.com/family-law – the site owner will have to obtain links to each individual subdomain that are topically focused.
This might be easier to see visually:
This is assuming each link is equal, which would never happen in reality. But if it did, each site would have some links pointing to it.
If you do a really good job of internal linking between the subdomains, then there may be some overlap and shared value.
However, if you start with one main domain and then obtain links to subfolders (all part of the same site), you’ll have 63 total links pointing to the main subdomain or domain you’ve chosen to use:
In both of these examples, it’s up to you as a site owner how you would like to design, develop, and maintain your site(s).
Unless there’s a compelling reason to separate business units, the subfolder approach is far less work.
Because it is less work, you’re more likely to maintain it, which will likely translate into better rankings.
Summary
If you want to do the work of building out separate entity profiles and link value for multiple subdomains, go right ahead. Google really doesn’t care whether they rank subdomains or subfolders.
But if you’re maxed out on time fully optimizing one domain, let alone multiple domains, then subfolders are probably a better option for you.
