I would have to disagree with you here. When I back up my computer, I use CDs. I also back up almost everything. I don't distinguish between pictures I might like, and those I might not like. It all gets backed up on cds. If I had gotten some porn popups or the like on my drive, most likely they would have been backed up on my cds, not because I wanted to keep them, but because I'm fairly lazy as computer users go. Some people back up on zip disks--Westerfield also had zip disks. I do not necessarily assume what was on the cds and zip disks were there because he wanted to keep those images.
The spam pop-ups literally froze the computer, but they kept running a loop amongst themselves. Couldn't get back to Google, couldn't get to my task-bar screen, couldn't even Control-Alt-Delete to shut down those VanDam things. I had to turn off the computer and run scan-disk just to get back to the internet. I'm willing to bet money, though, that I now have "INCEST!! Click here for more!" websites stored on my hard drive, along with the accompanying pictures from that ad page. Help!
P.S. Irony of it all...the software program I was looking for info about when I clicked on that link was firewall program Zone Alarm! Have now downloaded ZA from their website and have it running in conjunction with WindowsXP's firewall.