The PC causing the spam flood could easily be yours. (You can buy this neat picture of a zombie, by Wayne Renolds, from the OnlineGamesCompany.)

Viruses pushed by spammers have turned millions of home PCs into "spam zombies" which now push 80% of the sludge that is out there.

Sandvine's study cross-referenced SORBS data on IP addresses used to send spam against its own study of PCs bypassing their home mail servers.

Sandvine's most radical conclusion is that ISPs filter traffic within their networks, and stop depending on end users to maintain security. (Another option, offered by Network Associates, is "behavior blocking" software.)

The Register, whose coverage of this story puts that of U.S. media to shame, also tied in the 21-year old German author of the Phatbot trojan to the trend. The publication also described how spam fighters are now infiltrating spammers' own online clubs and confirming the growing link between virus writers and spammers.

I've said before that I fully expect organized crime to take over spamming very soon. The combination of real criminals and spammers (who claim to be legitimate businesspeople) is one data point down that road.