Some persons have commented that I didn’t discount the click fraud factor. The reason why I didn’t is that the motivation of the persons who clicked on my ad doesn’t matter at all. If it’s a person clicking on a “malicious” ad to commit click fraud, the result is the same: the cybercriminal gets a shot at trying to infect his machine.
And if it’s a program instead of a person doing the click fraud, the result is also the same if it’s a Windows program using the MS IE ActiveX component. I’m waiting for feedback to try to quantify the amount of non-Windows automated click-fraud that could have impacted my Google Adwords campaign. I’ll post an update when I get said feedback.