If you post to a newsgroup with a fake reply to header, people sending replies to you can become very unhappy when their replies bounce back to them. Using a bogus domain name can result in an unsuspecting, but legitimate, domain being sent your email. Another approach that may fool spammer's automated e-mail address grabbers is to lookup your Internet Service Provider's POP server, and insert the numeric values as your return address. Here is more technical information on how so specify e-mail addresses. You can also check how secure your browser is.
Spammers use spambot spiders to pick off e-mail addresses from web pages.
Or, simply include one of the following links on your web pages. Spam spiders will follow the links and pick up the bait, which might just cause them to send to bad e-mail addresses, spam themselves, etc. Wpoison is a free tool which can be used to help reduce the problem of bulk junk E-Mail on the Internet. Yahoo has a multitude of spambot bait sites listed. If Senators and Representatives receive more and more spam as they use the Internet, they will begin to realize the consequences of unregulated spamming.