If you want to register a domain to ensure that nobody else is going to take it, however, you have not created the website for it yet, you can park it. It's a feature that registrar companies provide whenever a domain is not connected to any web or email hosting service. That way, you are able to protect a brand name, for instance, and you will own the domain name in question although it will not open any content. If you would like, you may choose some standard template that the registrar offers, like For Sale or Under Construction, alternatively you can forward the domain name to a new web address. Your second option is extremely helpful in case you own a number of domains, but you want every one of them to open the same site. For instance, you can register domain.net and domain.org, then park them and direct them to domain.com. In this example, you'll need hosting for the third domain address only and the traffic to the other ones is going to be redirected to it.