Spam is the scourge of the Internet. It clogs inboxes, crashes servers, wastes time and money and is an abuse of privacy. More than half of the two trillion e-mail messages sent in 2006 are likely to be spam. According to the anti-spam Web site Spamhaus Project, about 200 spammers worldwide are responsible for about 80% of all spam in Europe and North America. There are an estimated 2,300 spammers in the US.