Spyware and its close relatives are a major impediment to the further development of electronic commerce. A Los Angeles Times article entitled Breaking, Entering Your PC gives a good idea of how damaging such attacks can be:
Spyware is by far the most common category of complaints received by software and computer manufacturers. It is responsible, for example, for up to "one-third of operating system crashes reported to us," said Paul Bryan, who works in Internet security at Microsoft.Thanks to Bag & Baggage for the link. beSpacific has more links.