I have a theory about viruses

[MetalMilitia]

Most viruses work to create a vast bot-net of PCs that can be called upon to perform some task. People make money from selling usage time of this bot-net. So for example you can buy a million PCs to perform a denial of service attack on some website for a few days or whatever.

[DirtySanchez]

i like the pop up adds that sell pop up blocker software