Never respond to a spam e-mail. For a spammer, one "hit" among thousands of mailings is enough to justify the practice. Instead, if you want a product that is advertised in a spam e-mail, go to a Web site that also carries the product, inquire there, and tell them you do not approve of spam methods and will not patronize a company that uses spammers.
Never respond to the spam e-mail's instructions to reply with the word "remove." This is just a trick to get you to react to the e-mail -- it alerts the sender that a human is at your address, which greatly increases its value. If you reply, your address is placed on more lists and you receive more spam.
Never sign up with sites that promise to remove your name from spam lists. These sites are of two kinds: (1) sincere, and (2) spam address collectors. The first kind of site is ignored (or exploited) by the spammers, the second is owned by them -- in both cases your address is recorded and valued more highly because you have just identified it as read by a human.
Never mail-bomb spam sites or engage in hacking to stop spammers. This only increases the amount of wasted Internet traffic, creates sympathy for spammers, and makes the Internet even less reliable than it already is.
Take meaningful action to stop spammers. Filter their messages or their sites using the methods described below, write their host sites (without revealing your real e-mail address!) and any sites that are used as relays, write your congressional representatives.