If you want to register a domain to make certain that nobody else will take it, however, you have not created the site for it yet, you could park it. It's a feature that registrar companies provide if a domain is not linked to any web or e-mail hosting service. By doing this, you can protect a brand name, for instance, and you will own the domain name in question although it won't load any content. If you'd like, you can choose some standard template that the registrar offers, like For Sale or Under Construction, you can also direct the domain to a different web address. Your second option is very useful in case you own a number of domains, but you want each and every one of them to open the same site. For example, you can register domain.net and domain.org, then park them and direct them to domain.com. In this example, you're going to need hosting for the third domain only and the traffic to the other ones will be redirected to it.
