[Immo]

I always use subdomains to split sites up.

I used to do hosting, design and marketing and had each as its own subdomain.


It kind of works for 2 reasons;

1. You can place similar things in their own space.

e.g.

marketing.domain.ext/ppc/
marketing.domain.ext/seo/
marketing.domain.ext/press-releases/

etc


2. Each individual element and subsequent links into it help the other sections of the site more than if they where subfolders.