I'm confused about the Customer Portal & Creators Users's and permissions links. I have the "new" account setup

So under Application Settings i have links to the following:

Users & Permissions: Which has Users, Roles, Profiles and Field Permissions

Customer Portal: which also has has Users and Profiles etc

So when a customer registers for access i can see him in the Customer Portal and he gets assigned a profile from the Customer Portal. So what is the purpose of the Users/Roles/Profiles under <Users & Permissions>?  

If i check under <Users & Permissions> the registered client doesn't show up there and the profiles also don't show up there from the Customer portal

I'm confused by these two links - which one should i be using to manage Users, Roles and Profiles, or are they somehow complementary?

thanks