If you'd like to register a domain to make sure that no one else is going to take it, but you haven't developed the web site for it yet, you could park it. That is a service that registrar companies provide if a domain name is not connected to any web or email hosting service. In this way, you'll be able to protect a brand name, for example, and you will own the domain name in question although it will not load any content. If you'd like, you can choose some standard template that the registrar offers, like For Sale or Under Construction, alternatively you can direct the domain to a different web address. Your second option is extremely helpful in case you own a few domain names, but you want every one of them to open the same website. As an example, 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 only and the traffic to the other ones is going to be redirected to it.