Today I got a cryptic message from my ISP.

"It has been brought to our attention that a PC in your home may be compromised with a computer virus. Please ensure that you have virus software that is updated on your computer and run a virus scan as soon as possible.

In an effort to maintain the integrity of our network, your outgoing e-mail capabilities have been temporarily blocked.

Once you have identified and resolved the virus issue, please contact our Customer Care Center at the number below to have your access restored."

Talk about a passive way to stop spam. I'm on an all-Mac network, BTW.