These days, spam is a multimillion-dollar industry. It generates millions of dollars for the spammers, millions for the companies that produce antispam solutions, and millions for the people who install and support those solutions.
Some people think that individuals who go after spammers on their own are vigilantes. Calling such people vigilantes implies that we should all sit around on our duffs while we let our respective governments make and enforce laws such as the Controlling the Assault of Non-Solicited Pornography and Marketing (CAN-SPAM) Act of 2003. As time has shown, the act works to some extent, but it has problems and it's nearly useless when a spammer is located anywhere outside the United States.
Meanwhile, other spam-fighting methods, such as Domain Keys Identified Mail (DKIM), Sender ID, and other technologies (some of whose real motives are questionable,) try to place controls on email flow. Most of these technologies will lead to increasing restrictions on email flow over time and could severely limit open and free communication, which in my opinion is anti-Internet.
Blue Security (at the URL below) has a tool called Blue Frog that seems to be an effective antispam defense. Individuals and businesses can put their email addresses on Blue Security's encrypted "do not spam" list. A user on the list who receives a spam message can notify Blue Security, which investigates and then notifies the proper authorities about offending spammers. Blue Security also sends an opt-out message to the spammer for each message sent to a Blue Frog user. If a spammer sends five spam messages to 1 million Blue Frog users, the spammer receives 5 million opt-out requests. This places a tremendous load on a spammer's resources, and rightly so.
Last week, Blue Security found itself under attack. Apparently, a spammer became so angry at the influx of opt-out messages that it decided to launch a Distributed Denial of Service (DDoS) attack against Blue Security's network. The result was that the spammer (PharmaMaster) was exposed as the low-life scum that it is, so people can choose not to do business with it. Also, Blue Security received a ton of press coverage due to the attack, which will undoubtedly raise awareness about Blue Frog by many orders of magnitude.
You can read more about the incident at the URL below. Kudos to Blue Security are in order for helping people take matters into their own hands while acting as a team. According to a press release from Blue Security, six of the top ten spammers worldwide have stopped sending spam to users of Blue Frog. If every Internet user had technology similar to Blue Frog, the spam problem could be cured very, very quickly. Such technologies minimize the need to legislate or build solutions that could potentially limit the openness of the Internet.