There are 2 services that you’ll need for a working site - a domain name plus a hosting plan for it. Any time you type the domain address in your web browser, you see the content that’s uploaded inside the web hosting account, but if that domain address isn't linked to such an account or to an email service, it is parked. Put simply, the domain address is registered and you're its owner, but it doesn't have any content of its own. Instead, 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 benefit of parking a domain address is that you can keep it and make sure that nobody else will take it. At the same time, it won't block a slot for a hosted domain in your account. You could also park domains if you have a .com, for instance, and you register domains with other extensions such as .net, .org or country-code ones to direct them to the main website so as to protect a brand name.