BusinessWeek's cover story about click fraud has lots of good and fresh reporting on the subject. Not sure I go along with the conclusion, though. In the last paragraph, the story quotes a marketing professor who predicts that continued fraud is going to "scare away the further development of the Internet as an advertising medium."
I think that's a bit dire. Yes, click fraud is a serious problem. It will push more research will into fraud detection. This will lead to further development of Internet advertising technology, a more sophisticated understanding of network dynamics, and new services. Those companies that do a better job of providing clean results will be able to charge a premium. In the meantime, advertisers are happy to use click fraud for leverage to wrest refunds and other concessions from the search engines.
The other question (which the story didn't cover): Will the menace of click fraud on the Internet send more advertising scurrying back to papers and magazines? Hmmm. I'll keep quiet and listen to your thoughts.