Think of Parked Domains as another way to reach an existing site, for instance, you are at home, you have a cellular phone and home phone, on one number I call I reach your cellphone, and you, on the other I reach your home phone and you. Either way, I call, I will reach you. The same can be said for Parked Domains, with many domains or telephone numbers to reach one site. Your site can be loaded without any knowledge of the true sub-domain user.example.com if you park example.net on top of it and only reference and use example.net in your site and literature.
According to the viewpoint of a website admin, the contrast among Parked and Addon Domains is basically this, with Addon Domains, you construct a totally independent webpage, with Parked Domains, it is as of now assembled, you simply are giving it another phone number for the webpage it is stopped on.
As with Addon Domains, you must change the nameservers in your domain registrar control panel first prior to :