There are two separate services you need for a working web site - a domain name and a web hosting plan for it. Any time you type the domain name in your web browser, you see the content that is uploaded inside the website hosting account, but if that domain is not linked to such an account or to an email service, it is parked. To put it differently, the domain is registered and you're its owner, but it lacks content of its own. As a substitute, it can open either a pre-made “Under Construction / For Sale” page from the registrar company, or it may be forwarded to any other URL of your choice. The main advantage of parking a domain name is that you can keep it and ensure that no one else will take it. Meanwhile, it won't take a slot for a hosted domain within your account. You may also park domain names if you have a .com, for instance, 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.