what about having an address book in another (small) program? I mean surely a simple virus like these mass mailing ones couldn't open up another program unless there was a serious security hole in the mail client, or unless the virus itself was something more serious then a simple virus.
the virii compile on load....(when the email is opened or attach is opened). it would just require one more line of code to get it to open another prog... not to difficult for the skilled programmer.