Registering a domain and hosting one is commonly mistaken by a lot of people to be one and the same thing. They are in fact two separate services - the domain registration is the actual name and nothing else, while the hosted domains feature refers to the number of already registered domain names you can accommodate within the same hosting account and have site files and e-mails for them. Your sites will function in exactly the same way no matter whether the domain names 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 enable you to have a site if you don't host this domain address in some account so that records for it are created and it starts opening the information from that account.