During the English SEO office hours from September 17th, 2021, someone asked Google Search Advocate John Mueller a question, to which he had a bit of a funny response.
John’s response was, “Oh my gosh. I don’t know if someone is trying to troll us again.
“We, from our point of view, when we talk with the Search Quality Team, they say subdomains and subdirectories are essentially equivalent.”
A few moments later, John reconfirms Google’s stance on this:
“Some people in the SEO world have very strong opinions, and if we say [that] it doesn’t matter and someone else says, ‘You should do it like this,’ and you want to follow their advice, then it’s like, ‘Go ahead and do that,’ because…from our point of view…we say, ‘It doesn’t matter.’
“You Can Put Your Content However You Want”
When John said that “You can put your content however you want,” I believe he was talking about how your site, including the subdomains and directories, is structured.
Things to Consider
Do you want a certain section to be in a subfolder or a subdomain?
If you have an international site (and if you do, be sure to read below about geo-targeted domains), and your TLD is a non-geo targeted one (again, see below), you can dedicate certain subdomains or subfolders/sub-directories to certain countries.
WordPress (if you decide to use that as a content management system) usually installs onto the root of your domain, a subdomain, or sub-directory. As far as I know, it doesn’t install onto multiple directories.
So, if you had multiple subdomains and sub-directories, each may have to have its own installation of WordPress. That means that each user would have to have a login for each installation, and it can get tricky trying to manage all of those logins, updates, plugin installations, etc.
Those are things you need to thoughtfully consider.
John continued about other things to consider:
“I think that there are a few aspects that play a role there, which are less around SEO, but more around things like reporting is ‘How easy is it to set these sites up?‘
“Do you want to track their performance separately on separate hostnames or together in one hostname?”
Then, he mentioned something about how Google might see things: “It’s also something where we might treat things on a sub-domain slightly differently because we think, ‘Maybe this is more like a separate website versus all of the same website,’ so those things can all play a role there.
“In practice, what I would say is, ‘Try to focus on your infrastructure first, and see what makes sense for you, and then work on that.’
“And if you’re working together with an SEO who has a very strong opinion and everyone else is like, ‘Whatever you want,’ then…I don’t mind… if you follow their opinion either, because that should work too.”
But, Unless Your TLD is Non-Geotargeted, You Can’t Geographically Target Subdomains or Folders
Basically, if your TLD (top-level domain) is a geo-targeted one (such as a country TLD like .ca for Canada, .co.uk for the UK, and so on), then from a Google SEO perspective, you can’t have directories or subdomains for countries other than the one designated by the TLD. So, for example, if you have a .ca TLD (say, mysite.ca), you can’t really have united-states.mysite.ca or mysite.ca/france, because your TLD is geo-targeted exclusively for Canada).
So, in short, Google sees subdomains and sub-directories as equivalent. If you’re wondering about domain authority, my impression is that a subdomain (or sub-directory) would benefit from the domain authority of the root domain.
Ultimately, what you decide to do comes down to carefully considering some of the things I mentioned here.