You share your server with other domains. Each account (Telnet, FTP or Email) is setup as a user on the server. If you try to add a user in your SiteMadeEasy Web Control Panel (http://yourdomain.com/cgi-bin/plusmail) and receive the message
User exists. Choose another username.
it just means that the username you chose has already been taken by another domain. A username can be used only ONCE per server.
You can get around this by using a simple redirect that will make the name valid and just redirect email to a valid POP box. All this means is that you use another login to retrieve email, you do not need to use it in your email addresses.
To direct email sent to email@example.com into another email box, simply add this email redirect:
and create the pop account firstname.lastname@example.org. When your email program connects to 'yourdomain.com' and logs in as 'orders4us' you will get the email that was sent to 'email@example.com'.
There is also an extensive online manual available.
http://hostings.com 888-404-HOST (toll-free US/PR/VI/GU), 706-897-4743