Registering a domain name and hosting one is frequently mistaken by many people to be one and the same thing. They are actually 2 different services - the domain address registration is the actual name and nothing more, while the hosted domains feature refers to the number of already registered domains that one could accommodate within the same web hosting account and have site files and emails for them. Your sites will work in precisely the same way regardless of 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 enable you to have a web site if you don't host this domain address in some account so that records for it are created and it starts opening the data from that account.