Joe Holcomb, the Senior VP of Marketing of BlowSearch recently wrote a detailed article on the problems with click fraud. It's a somewhat lengthy two-parter, including some promotional material, but worth a read to anyone concerned about click fraud.

He's a big fan of PPC and feels that it can be successful despite its flaws. Personally, I have never understood the industry's love of PPC advertising. In fact, I have never understood some people's desire to track all clicks, even those that aren't related to advertising. I think it imposes unnecessary costs on the search engine and is too prone to abuse.