What is a subdomain?
A subdomain is a subdivision of your main domain — for example, blog.example.com or shop.example.com. Subdomains have their own content and, importantly, search engines treat them as separate entities from the root domain.
Why subdomains matter for SEO
Putting content on a subdomain can split your authority: links to blog.example.com help that subdomain, not example.com’s rankings directly. For most sites, subfolders (example.com/blog) consolidate authority better. Subdomains make sense for genuinely separate products or geographies.
Subdomain vs subfolder
- Subfolder (example.com/blog): shares domain authority — better for most SEO.
- Subdomain (blog.example.com): separate entity — useful for distinct brands or apps.
- ccTLD (example.co.uk): strongest geo signal, separate domain entirely.
Subdomains and GEO
AI systems may treat subdomains as separate brands. If your main brand is on the root domain, keep supporting content there to preserve entity clarity.
Related terms
How Social SEO Team can help
We advise on the right structure for your goals. See our SEO services.