Mark Cuban thinks it is a bigger problem than imagined:
4. The Bad Guys have figured out that the risk of proving they are breaking the law with click fraud is minimal. Try explaining the difference to authorities between a blog, a splog and a website that is trying to make money from any of the many, many affiliate marketing programs that also happens to host adsense or other ad publishing network ads.
5. The Bad Guys have figured out that they look a lot more legit getting checks from google than trying to wash 10k dollars in cash delivered in a bag.
6. The Bad Guys have figured out that untold amounts of dollars are being spent on an ongoing basis by the biggest companies in the world to try to stop them from stealing data that has disputable value and is difficult to sell. Why waste time there when search engine companies, even with the maybe 20 best and brightest assigned to the problem are no match for the legions of hackers around the world who see the easy money and are happy to grab it.