My aunt got the same virus pictured in that article (WARNING! YOUR'RE IN DANGER!). Rebooted in Safe mode and used autoruns to find the app. I asked her what she was doing when she got infected. She loaded up her Yahoo mail, ** went to the SPAM folder **, and opened up an email titled "Olive Garden Coupon For You". It looked sort of valid except that Yahoo had blocked all the images. Mousing over one of them showed that they referred to an exe hosted by ygztcrsk.com (some random hostname). I told her to stay out of the Spam folder; it's there for a reason :)
The infection itself was minimal compared to other PCs I've cleaned. One had a TDSS Rootkit on it that no virus scanner would find; after 30 minutes or so it would start downloading other viruses that the scanners would catch, but never the original.