Just out of my curiosity, I decided to test Prevx on my work laptop today.
During its initial scan, it reported 7 infections.
All of these were false positives.
Some of them were reported as "High Risk Rootkits" while the files were in fact drivers of my network card (T-mobile wireless card).
So I guess this explains how the stats on their homepage get computed (and how relevant they are, really).
I guess I'm just not ready for this Collective Intelligence thing.