If you'd like to register a domain to make sure that no one else is going to take it, but you haven't built the site for it yet, you could park it. This is a service that registrar companies offer whenever a domain name is not 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 name in question although it won't open any content. If you'd like, you can choose some default template that the registrar offers, like For Sale or Under Construction, or you can direct the domain to a new web address. The second option is extremely helpful in case you own a few domain names, but you want every one of them to open the same website. As an example, you could register domain.net and domain.org, then park them and direct 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.