There are two separate services that you’ll need for a functioning site - a domain name and a hosting plan for it. Any time you type the domain address in your browser, you see the content that is uploaded inside the website hosting account, but if that domain name isn't linked to such an account or to an email service, it's parked. To put it differently, the domain address is registered and you are its owner, but it doesn't have any content of its own. Instead, it can open either a pre-made “Under Construction / For Sale” webpage from the registrar company, or it could be directed to any other URL of your choice. The advantage of parking a domain name is that you can keep it and make sure that no one else is going to take it. In the meantime, it's not going to occupy a slot for a hosted domain within your account. You may also park domain names if you have a .com, for example, and you register domains with other extensions like .net, .org or country-code ones to direct them to the main site so as to protect a brand name.