The article was created in 2000. Viruses are pretty non-existent for Palms because most older Palms are not directly connected to the internet. Viruses require mass infections to survive and standalone Palms can't offer mass infection in a short time.
After saying that, once the Treos start getting mainstream and more popular, I'm sure that they will start surfacing.
Yes, I agree that a regular backup is probably best.