There are two separate services you need for a functioning website - a domain plus a web hosting plan for it. Each time you type the domain in your Internet browser, you see the content that’s uploaded inside the hosting account, but if that domain address isn't linked to such an account or to an email service, it is parked. To put it differently, the domain is registered and you are 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 can be forwarded to any other URL of your choice. The advantage of parking a domain name is that you can keep it and make certain that nobody else is going to take it. Meanwhile, it's not going to occupy a slot for a hosted domain inside your account. You may 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.