BigDave - 7:20 am on Oct 24, 2006 (gmt 0)

Click fraud is to online advertising as shoplifting is to retail sales. It is a cost of doing business.

In both cases you try and stop the most egregious cases to keep it from becoming commonplace. But at a certain point the policing actions start costing more than the amount lost. In most cases this point is reached at a very small percentage of the losses.

If an advertiser's campaign is successful even with some fraud, they would be foolish to stop the campaign just to try and teach Google a lesson.