SEOs have argued about this for as long as I can remember. Many SEOs say that subdirectories are better for SEO and insist on using them. This is a myth that’s persisted based on some old studies. Google has repeatedly said either is fine. It’s silly to argue if a path is better on the left or the right. Without going into too much technical detail, these paths are virtual in most modern systems, which means they don’t even point to actual locations on a server. You can change their name and their location in the URL structure in a matter of minutes. Think about that for a second; you can change. A subdomain to be served as a subdirectory quickly and without changing anything.
People think it’s important
Where the path is located in the URL? Many SEOs believe that subdomains are treated as separate domains. But the truth is more complicated. Anyone that incorporates subdomains as a main part of their site will likely have them treated as part of the site. However, if you’re not treating the subdomains as part of your main website. Read as not connecting them with internal links), then they may be treated as separate. The same is true for subdirectories. If you don’t treat them as part of the same site, Google may not either. Gary Illyes confirmed this at Pubcon in 2023. He said it’s not common on the English web, but it is in other languages.
A little history lesson
SEOs abused this. Google closed this loophole in one of the old domain/host clustering updates. These days, subdomains are likely to be treated as part of. The same website if they appear to be part of the same website. Even sitelinks include links to subdomains. I can give you countless examples where various subdomains show as sitelinks for. The brand—Github, LinkedIn, Google, Amazon, Microsoft, Yahoo, Netflix, Walmart, etc.
Therefore SEO case studies. Let’s look at one of those case studies and what I see. Using Top Pages 2.0 in Site Explorer, you can click and drag on the history chart to see. The difference between any two dates. In the case of mention.com, they migrated from a subdomain to a subdirectory in January 2016. I really don’t see any difference in that period. It’s only after that when they started adding additional content that I see their traffic growing.
