There are a lot of ways to forward traffic from one domain/website to another. The so-called URL redirection is often preferred. In contrast to parking a domain address, a URL forwarding can be done only if the domain in question is hosted. What this means basically is that you could still open any content if you have a direct link to it and you can set up e-mail addresses or subdomains and use them. This type of function has lots of practical uses - if you want to switch your domain, you could forward the traffic, but the emails with the old one will still be active in the event that you are communicating with clients or partners. When you have 2 identical sites and you intend to rebuild one of them, you may forward the traffic to the other website to avoid losing potential clients, while you shall still be able to access the admin area for the first website and develop it.