Registering a domain and hosting one is commonly mistaken by many people to be one and the same thing. They're in reality 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 you can accommodate in the same web hosting account and have site files and emails for them. Your sites will function in exactly the same way regardless if the domain addresses are registered and hosted at the same place or are registered with company A and pointed to company B. Simply registering a domain without hosting it will give you ownership, but will not allow you to have a site until you host this domain name in some account so that records for it are set up and it starts opening the information from that account.