If you'd like to register a domain to make sure that no one else will take it, but you have not built the website for it yet, you may park it. This is a service that registrar companies provide whenever a domain name isn't linked to any web or e-mail hosting service. This way, you can protect a brand name, for example, and you'll own the domain address in question although it won't open any content. If you want, you can pick some default template that the registrar provides, such as For Sale or Under Construction, or you can forward the domain to another web address. The second option is very helpful if you own a few domain names, but you want every one of them to open the same website. For example, you can register domain.net and domain.org, then park them and forward them to domain.com. In this example, you're going to need hosting for the third domain only and the traffic to the other ones is going to be redirected to it.