When you decide to add a blog, a store, or a knowledge base to your existing website, one of the first decisions you face is structural: where does the new section live? The two most common options are a subdomain (blog.yourcompany.ca) or a subdirectory (yourcompany.ca/blog). They look similar, but they behave quite differently in the eyes of search engines.
What Is a Subdomain?
A subdomain is a prefix added before your main domain name. Common examples include:
blog.yourcompany.cashop.yourcompany.casupport.yourcompany.ca
From a technical standpoint, a subdomain is treated as a separate hostname. Your DNS settings point it to a specific location, and it can even run on a completely different server from your main site. This independence is both a feature and a limitation.
What Is a Subdirectory?
A subdirectory (also called a subfolder) is a path that exists within your main domain:
yourcompany.ca/blogyourcompany.ca/shopyourcompany.ca/support
The content lives inside your existing website structure. From a server perspective, these pages are part of the same site as your homepage.
How Google Treats Each Option
Historically, Google has treated subdomains as separate websites. This means that links pointing to blog.yourcompany.ca build authority for the subdomain separately from links pointing to yourcompany.ca. If your main domain has spent years accumulating backlinks and trust, a new subdomain starts largely from scratch.
Subdirectories, on the other hand, benefit directly from the domain authority your main site has built. When yourcompany.ca earns a link from a respected Canadian news site, that authority flows throughout the domain - including your /blog and /shop paths.
Google has said that it can "figure out" subdomains and associate them with the main site, and there is truth to that. But in practice, the SEO community consistently observes that subdirectories outperform subdomains when all other factors are equal. Major SEO tools like Ahrefs and Moz track domain metrics that reinforce this pattern.
The Practical Recommendation
If your goal is to build search visibility and organic traffic, use a subdirectory whenever possible. Moving your blog from blog.yourcompany.ca to yourcompany.ca/blog often produces a measurable improvement in rankings over the following months as the consolidated authority takes effect.
This is the approach taken by most high-performing content websites. HubSpot, for example, consolidated their blog under their main domain years ago and documented significant SEO gains as a result.
When Subdomains Make Sense
There are legitimate reasons to use a subdomain, even accepting the SEO trade-off:
Technical separation. If your blog runs on WordPress but your main site is built on a custom platform, a subdomain makes the technical setup much simpler. The two systems can run independently without interfering with each other.
Different language versions. If you serve content in both English and French, fr.yourcompany.ca is a common and acceptable structure for a separate French-language experience.
Staging and development environments. staging.yourcompany.ca or dev.yourcompany.ca are natural subdomain uses. These should be blocked from search engines anyway, so the SEO consideration does not apply.
Separate applications. If you run a web application (like a client portal or SaaS dashboard) that is fundamentally different from your marketing site, a subdomain makes organizational and technical sense.
Real-World Examples
Consider a Canadian accounting firm that wants to add a blog to attract small business clients through organic search. The firm has been operating smithaccounting.ca for four years and has built modest domain authority through directory listings and client referrals.
If they launch blog.smithaccounting.ca, their new articles compete for rankings independently of the established domain. If they launch smithaccounting.ca/blog, every new article benefits immediately from the four years of trust the domain has built.
For a small business adding content marketing to their existing site, the subdirectory approach is almost always the right call.
Making the Switch
If you currently have a blog or store on a subdomain and want to move it to a subdirectory, the migration is straightforward but requires care: set up the new subdirectory location, migrate your content, implement 301 redirects from every old subdomain URL to the corresponding new subdirectory URL, and update any internal links. Done properly, the transition preserves your existing rankings and positions you for stronger performance going forward.
