> Only arrests will help bring about the serious reduction in spam many dream of.
The way to stop spam is to kill off the botnets. The basic attribute of the criminal mind is the assumption that they won't get caught. No crim. performs a risk-reward assessment before embarking on a course of action. They all assume that the risk of getting nicked is small or insignificant (or that the punishment will be 10 minutes on the "naughty" step). Therefore arresting spammers will only take those individuals off the internet: it won't stop new ones taking their place.
The only way to stop spam as a whole is to deny the spammers access to the millions of machines that send out their content. Without those, they have no practical means of either infecting new machines or or sending out enough messages to make a 1 in a million conversion rate a viable way of turning a profit. If we considered spam like we think of disease, the "treatment" would be to attack the infection, "cure" the machines and ensure they are immune to further attacks. What's the best way to do that? Probably to use a "if you can't beat 'em, join 'em" philosophy and have some very clever people build their own viruses that shut down infected machines and beef-up their security using exactly the same security holes that got them infected in the first place.