If you wish to register a domain name to ensure that nobody else will take it, however, you haven't developed the web site for it yet, you could park it. That is a service that registrar companies offer when a domain name is not linked to any web or email hosting service. That way, you are able to protect a brand name, for example, and you'll own the domain address in question although it will not open any content. If you would like, you can choose some standard template that the registrar offers, such as For Sale or Under Construction, alternatively you can forward the domain to an alternative web address. Your second option is very helpful in case you own a number of 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 only and the traffic to the other ones is going to be redirected to it.