I mentioned this story a while back, it seems that Google is trying its best to fight fraudulent ad clicking on its adsense program. As time goes on no doubt the clickers and the search engines will become much more sophisticated.
Google declined an interview for this report, citing the mandatory “quiet period” before its initial public offering, which is expected to raise $2.7 billion. But the company said in a statement that it has been “the target of individuals and entities using some of the most advanced spam techniques for years. We have applied what we have learned with search to the click fraud problem and employ a dedicated team and proprietary technology to analyse clicks.”