geeks who had watched WarGames too many times and figured if Matthew Broderick could start a nuclear war on a 1200 baud modem they could rule the world with their 56K. Some may have been written by sociopaths just wanting to stir up trouble or maybe some were from hackers testing themselves, as if the ability to erase your neighbors vacation pictures is a survival skill. Whatever the beginnings, I believe they have been co-opted, like most things eventually are, as another tool of advertising.
Think about it. What did the last virus you had on your computer actually do? Mine locked down my system so that the only thing I could run was my Internet browser and then it hijacked it so that every page eventually lead me to a website where I could buy antivirus software. As if! Isn't that like attacking somebody with a butcher knife and then selling them an adhesive bandage? And if you agree with that analogy, it's not that big a leap in logic to think that the computer equivalents of Johnson & Johnson may be buying stock in Ginsu.
Unfortunately, for the service industry, I'm not the only person that has reached this or a similar conclusion. During the debut of the MSblast worm I was working at a local computer store where customer after customer were bringing their computers to be diagnosed for $70 and disinfected for another $70. More than one person accused us of releasing the virus ourselves. Rather a narrow view of the issue, I thought.
Speaking for myself: I do not write viruses, nor do I kick back any of my salary to those that do. I find viruses to be just as annoying as you do. No. Probably even more so because I get to watch the same semi-computer-literate people reinfect their computers time and again and then blame me for it. And for that little bit of frustration I will cash in the overtime, thank you very much.
In the end I have learned two things that go a long way to preventing your computer from being infected:
1) Don't click on anything in a pop-up window. Just click the X to close it.
2) Buy a Mac. There has been one major virus that attacked the MacOS in the last 5 years.