Registering a domain and hosting one is commonly mistaken by a lot of people to be the same thing. They're actually 2 different services - the domain registration is the actual name and nothing else, while the hosted domains feature shows the amount of already registered domain names that one could accommodate within the same web hosting account and have site files and email messages for them. Your websites will work in precisely the same way no matter if 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 without hosting it will grant you ownership, but will not enable you to have a site unless you host this domain in some account so that records for it are created and it starts opening the content from that account.