Some commercial personal spam filters for PCs and Macs have also emerged recently, such as SpamKiller by Novasoft, Spam Buster by Contact Plus, and Mail Guard by Fundi Software. One claims to be pre-loaded with a list of 15,000 spam sites. They certainly will not work if you use Pine or elm on the Unix servers. Trying to reply to a spam message to complain to the sender is usually futile. While complaining to the ISP, you should also complain to the federal government .
Some spammers offer a method to be removed from their list .
In some cases, these are legitimate. Personally, I don't trust spammers. Complaining to the ISP may actually do some good. Few ISPs tolerate spammers and they will terminate the account right away when made aware of it. What you should NOT do is retaliate by mail-bombing the spammer or his ISP, attacking his site, threatening violence or vandalism, or the like.