[brudgers]

If I had to guess, it's all of them. By "them" I mean all the anti-virus packages that are targeted at consumers and small business. That seems to have been part of the business model starting over a decade ago. My guess is that the negative effects of anti-virus is what prompted Microsoft to first build free products and then eventually roll anti-virus into Windows.

I'd put it this way. My first inkling that something was wrong was when Norton Anti-Virus shifted to a subscription model and charged me full retail for a renewal back around 2006. What does disabling virus updates for ordinary users with the explicit intent of leaving them vulnerable says about a company's attitude in regard to long term trust?

I left Norton for Kaspersky and paid it protection money for a few years. It seemed refreshing at first. One day, a few years later, I learned how to look at my LAN traffic and saw how often I was sending data to its servers. It was more often than seemed reasonable. That's about the time Microsoft started providing its own free anti-virus and I started switching machines...the Windows XP Professional x64 box stayed on Kaspersky despite my misgivings until I upgraded it to Windows 7 because Microsoft did not port its anti-virus to that platform.

Spyware is often the basis for free software. Adobe Reader and Google Chrome and the Ask toolbar that shipped with Java are pretty obvious examples.