Subdirectory (yourbrand.co.uk/blog) inherits 90-95% of root domain authority. Subdomain (blog.yourbrand.co.uk) inherits 60-70%. Use subdirectory for SEO advantage.
Subdirectory vs Subdomain SEO
Google treats subdomains as separate sites. Blog on blog.yourbrand.co.uk doesn't fully benefit from yourbrand.co.uk's authority. Subdirectory /blog shares authority, ranks faster.
When Subdomain Makes Sense
Separate brand identity (community forum, knowledge base), different tech stack (blog on WordPress, main site on custom stack), distinct user experience. Otherwise: Use subdirectory.
Content Domain Portfolio
Main site: YourBrand.co.uk. Content Hub: YourBrand.co.uk/resources. Tools: YourBrand.co.uk/tools. Keep all content on root domain unless strategic reason to separate. Maximizes SEO efficiency.
Trademark Lens checks main domain availability - build content strategy on subdirectories for maximum SEO value from day one.