If you'd like to register a domain to ensure that nobody else is going to take it, but you haven't built the website for it yet, you could park it. It's a service that registrar companies offer if a domain is not linked to any web or e-mail hosting service. That way, you are able to protect a brand name, for instance, and you will own the domain in question although it won't load any content. If you want, you can choose some standard template that the registrar offers, like For Sale or Under Construction, alternatively you can forward the domain to another web address. Your second option is very helpful if you own a number of domain names, but you want each and every one of them to open the same site. 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.