If you want to register a domain name to ensure that no one else is going to take it, but you have not created the website for it yet, you may park it. That is a service that registrar companies provide whenever a domain isn't linked to any web or e-mail hosting service. That way, you are able to protect a brand name, for example, and you will own the domain in question although it won't open any content. If you would like, you may choose 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 extremely helpful if you own a few domain names, but you want all of them to open the same website. For example, you may 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 name only and the traffic to the other ones will be redirected to it.