Registering a domain and hosting one is frequently mistaken by a lot of people to be the same thing. They're actually two different services - the domain name registration is the actual name and nothing else, while the hosted domains feature reveals the amount of already registered domain addresses that one could accommodate in the same web hosting account and have website files and e-mails for them. Your sites will work in precisely the same way no matter whether the domains are registered and hosted at the same place or are registered with company A and pointed to company B. Simply registering a domain address without hosting it will grant you ownership, but will not allow you to have a site until you host this domain in some account so that records for it are created and it starts opening the information from that account.