Subdomain
Definition
A prefix added before your main domain, like blog.example.com. Creates a separate section that search engines may treat as a distinct website.
What is a Subdomain?
A subdomain is a prefix added to your main domain, creating what appears to be a separate section or site. In "blog.example.com", "blog" is the subdomain. Common examples include:
- blog.company.com
- shop.company.com
- support.company.com
- app.company.com
Subdomains vs Subfolders
The key difference is how search engines treat them:
| Subdomain | Subfolder | |
|---|---|---|
| URL example | blog.company.com | company.com/blog |
| SEO authority | Separate from main site | Shares main site authority |
| Technical setup | Separate hosting possible | Same hosting as main site |
| Analytics | May need separate tracking | Same tracking |
The SEO Debate
Google has stated they're generally good at associating subdomains with main domains, but SEO research often shows subfolders performing better for content that should boost your main site's authority.
The argument for subfolders: all content on company.com/blog builds authority for company.com. With blog.company.com, that authority might not transfer as effectively.
When Subdomains Make Sense
- Completely different applications (app.company.com)
- Different technical requirements
- Separate business units that shouldn't share authority
- International sites (uk.company.com)
- Very large sites with distinct sections
When to Use Subfolders Instead
For most businesses, keep your blog, resources, and service pages on subfolders (company.com/blog, company.com/services). This consolidates authority and is simpler to manage.
Unless you have a specific technical or business reason for a subdomain, subfolders are usually the better SEO choice.