In other words, "the Zombie apocalypse started a while ago and now we really may as well give up":
read more"Internet initiatives to close open relays have ultimately missed their intended purpose because spammers have created distributed botnets of zombie computers that contain malware with mail relaying capability. The number of clients under spammers' control is now so great that previous anti-spam countermeasures that focused on closing open relays are no longer effective."