If you'd like to register a domain to make sure that nobody else will take it, but you have not developed the website for it yet, you may park it. This is a feature that registrar companies offer if a domain is not linked to any web or email hosting service. By doing this, you can protect a brand name, for instance, and you will own the domain in question although it will not open any content. If you want, you can pick some standard template that the registrar offers, such as For Sale or Under Construction, or you can direct the domain name to another web address. Your second option is very useful if you own a number of domains, but you want each and every one of them to open the same website. For instance, 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.