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 number of already registered domain addresses which you could accommodate in the same hosting account and have site files and e-mails for them. Your websites will function in precisely 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 address without hosting it will give you ownership, but will not enable you to have a site if you don't host this domain in some account so that records for it are created and it starts opening the content from that account.