In order to make a web site, you need 2 things - a domain and a hosting plan for it. The domain registration is the actual website address which you enter in a browser to access a website, while the hosting space is where your site files is going to be. These are two tightly related, but independent services, although many people believe that registering the domain is enough. Very similar to the disk space and the monthly traffic features which a given hosting plan provides, there are a certain number of registered domain names you can add as hosted i.e. you can have the web content for them in some account even when the domains are actually registered through a different company. In technical terms, it does not matter if a domain name is registered and hosted with the exact same company or is registered with one company and directed to another - in either case your sites will function exactly the same way.