If you want to register a domain name to make sure that nobody else is going to take it, but you have not developed the website for it yet, you could park it. That is a service that registrar companies provide whenever a domain is not linked to any web or e mail hosting service. By doing this, you can protect a brand name, for example, and you will own the domain name in question although it won't load any content. If you wish, you may choose some default template that the registrar provides, such as For Sale or Under Construction, or you can forward the domain name to another web address. Your second option is extremely helpful 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 could register domain.net and domain.org, then park them and forward them to domain.com. In this example, you will need hosting for the third domain only and the traffic to the other ones will be redirected to it.