Spam. Nobody likes it. Everybody hates it. Yet it continues to exist, filling inboxes with unwanted offers for generic drugs, overseas lotteries, health insurance, and who knows what else. The problem can be especially bad if you've got a really old email address, and that email address has been listed on various websites over the years--spammers love to harvest emails from websites, making your old, established, and public addresses subject to an amazing bombardment of spam.