There are various 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 redirection is possible only if the domain name in question is hosted. What this means essentially is that you can still open any content in case you have a direct link to it and you can create email addresses or subdomains and use them. Such a feature has several practical uses - if you decide to switch your domain address, you may redirect the visitors, but the emails with the old one shall still be active in case you are getting in touch with clients or partners. When you have 2 similar Internet sites and you intend to rebuild one of them, you can redirect the traffic to the other website so that you can avoid losing potential customers, while you shall still be able to access the admin area for the first website and improve it.