Registering a domain name and hosting one is commonly mistaken by a lot of people to be one and the same thing. They are actually 2 separate services - the domain name registration is the actual name and nothing more, while the hosted domains feature reveals the amount of already registered domain names that one could accommodate within the same web hosting account and have website data and emails for them. Your sites 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 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 set up and it starts opening the content from that account.