I have uncovered evidence that the Yahoo Search Marketing fraud detection system might not be catching all of your invalid clicks. This means that you could potentially be charged for invalid clicks. I set up a test that Google Adsense caught right away. This test prompted some extended communication between their click fraud detection people and me. I firmly believe that Google Adsense has solved the problem, however as of this writing Yahoo has not shown genuine interest in improving their system. I am compiling a list of advertisers that would be interested in seeing how this flaw can be exploited and hopefully if a large enough group approaches Yahoo they will pay attention. If you are interested in being involved in this demonstration send me a PM with your contact info and I will include you in the mailing list.