If you wish to register a domain name to make certain that no one else is going to take it, however, you have not built the site for it yet, you can park it. It's a feature that registrar companies provide when a domain name isn't linked to any web or email hosting service. By doing this, you can protect a brand name, for instance, and you'll own the domain name in question even though it won't open any content. If you want, you can select some default template that the registrar offers, such as For Sale or Under Construction, or you can forward the domain to another web address. Your second option is very helpful if you own a few domains, but you want each and every one of them to open the same site. For example, you could 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 only and the traffic to the other ones is going to be redirected to it.