There are two separate services you need for a working web site - a domain name plus a website hosting plan for it. When you type the domain in your browser, you see the content that is uploaded inside the web hosting account, but if that domain name isn't linked to such an account or to an e-mail service, it's parked. To put it differently, the Internet domain is registered and you're its owner, but it lacks content of its own. Instead, it can open either a pre-made “Under Construction / For Sale” Internet page from the registrar company, or it may be directed to any other URL of your choice. The main benefit of parking a domain is that you can keep it and make certain that no one else is going to take it. Meanwhile, it's not going to block a slot for a hosted domain in your account. You could also park domains 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.