Apparently about eighty percent of spam is being generated by zombie machines (i.e., home computers that have been taken over by trojans, and are sending out massive emails without the owner even being aware).

Folks, if you don’t have at least a software firewall, like Zone Alarm (there is a free version), you are part of the problem. As cheap as hardware firewalls are these days, there is no excuse to have an unsecured machine with a permanent internet connection.