If you want to register a domain to make certain that nobody else is going to take it, but you have not created the website for it yet, you could park it. That is a feature that registrar companies offer whenever a domain isn't connected to any web or email hosting service. This way, you'll be able to protect a brand name, for instance, and you'll own the domain address in question although it won't load any content. If you want, you can select some default template that the registrar provides, like For Sale or Under Construction, or you can forward the domain to another web address. The second option is very useful in case you own a number of domain names, but you want every one of them to open the same site. As an example, you can register domain.net and domain.org, then park them and forward them to domain.com. In this example, you are going to need hosting for the third domain address only and the traffic to the other ones will be redirected to it.