There are two services you'll need for a working website - a domain and a website hosting plan for it. Each time you type the domain in your web browser, you see the content that’s uploaded within the hosting account, but if that domain name isn't linked to such an account or to an email service, it is parked. Put simply, the domain is registered and you're its owner, but it does not 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 can be forwarded to some other URL of your choice. The main benefit of parking a domain is that you can keep it and make sure that no one else will take it. Meanwhile, it will not block a slot for a hosted domain name inside your account. You could also park domains 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 web site as a way to protect a brand name.