h1. Sites

Site is the parent model of all pages, assets, ...etc. 

h2. Subdomain

A site must have a subdomain in case of all the other domains are not reachable (dns problems, ...etc). 

h2. Domains

When a request reaches the application, the site dispatcher method looks for a site responding to the domain name specified in the request. New domains can be added further by the administrator of the site. 
The very first domain is the one built from the subdomain.
A site must own at least one domain.

*Note:* domains like www.example.com and example.com are equals