14 comments so far, and none asking the question we should all be asking (maybe because it's obvious?) --
WHAT WERE THEY THINKING?!?
"The research asked 50 people from ten countries to surf the web unprotected and see what spam they picked up"
I'd like to know what "unprotected" means in this context. No firewall? No antivirus? No anti-spyware? No anti-spam? Java and Javascript allowed with no restrictions? Downloading anything you are prompted to (OK, most people probably do this one already)?
The only way I would recommend anyone even consider browsing with an unprotected system would be with a dedicated system used only for that task, a dedicated Internet connection used only for that system, and a certified letter from the researchers saying everything done was at their request, indemnifying the user of all responsibility. With everything out there (OS exploits, browser exploits, media player exploits, Safari's download-without-asking, etc) and all the possibilities (becoming part of a botnet, being used unknowingly for illegal p2p use, exploits/javascript download child porn images or "terrorist" materials, etc), it's just too risky. There's no way in hell I'd take the chance of the feds showing up at my door or risk being sent to jail to become part of a survey.