Just found this report about click fraud by Google claiming it is not as high as some of the bigger companies investigating click fraud such as Clickfacts,ClickForensics and Adwatcher report it to be. Have a nice day.
I always thought those figures were indeed exaggerated, but i guess Google wouldl say that, wouldn't they?
If I was G I'd say it wasn't a problem too. The SE that gets all that cash (billions) never has a problem taking it.