Your computer is considered a non-local host if you connect to our server from a network not under the ARInternet umbrella IP addresses. Of course, this does not prevent you from retrieving you mail but rather prevents non ARI computers from stealing proccessing resources to distribute E-mail. No one knows your there. Belive it or not it takes a good bit of work on your part to draw attention to your mailbox. There are several steps to keeping your anonymity.
News groups are spammer feeding frenzies.
Many sites require you to register your name and E-Mail address. Unless they are going to send you a password or other vital information don't give it to them. Spammers know that you don't want there E-Mail. Which is why most spam comes with a false return address. Only a trained individual, looking at the complete header information can determine where the messages are originating.