If you wish to register a domain to make sure that nobody else is going to take it, however, you haven't created the site for it yet, you may park it. That is a feature that registrar companies offer when a domain address is not linked to any web or email hosting service. By doing this, you'll be able to protect a brand name, for example, and you will own the domain name in question although it will not open any content. If you want, you can pick some standard template that the registrar offers, like For Sale or Under Construction, or you can direct the domain name to a new web address. Your second option is very helpful in case you own a number of domains, but you want each and every one of them to open the same site. For instance, you could register domain.net and domain.org, then park them and forward 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.