There are two services you need for a functioning website - a domain plus a web hosting plan for it. Each time you type the Internet domain in your web browser, you see the content that is uploaded inside the web hosting account, but if that domain is not 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. Rather, it can open either a pre-made “Under Construction / For Sale” page from the registrar company, or it may be directed to any other URL of your choice. The benefit of parking a domain name is that you can keep it and ensure that nobody else will take it. Meanwhile, it's not going to occupy a slot for a hosted domain address in your account. You can also park domain names if you have a .com, for example, and you register domains with other extensions such as .net, .org or country-code ones to direct them to the main site so as to protect a brand name.