There are 2 services that you need for a working web site - a domain plus a hosting plan for it. Each time you type the domain address in your web browser, you see the content that is uploaded within the hosting account, but if that domain name isn't linked to such an account or to an e-mail service, it is parked. Put simply, the domain name is registered and you're its owner, but it doesn't have any content of its own. As a substitute, it can open either a pre-made “Under Construction / For Sale” webpage from the registrar company, or it can be directed to some other URL of your choice. The benefit of parking a domain name is that you can keep it and ensure that no one else will take it. Meanwhile, it's not going to take a slot for a hosted domain address within your account. You could also park domain names if you have a .com, for instance, and you register domain names with other extensions like .net, .org or country-code ones to forward them to the main site so as to protect a brand name.