Click Fraud has arisen in recent months as an issue that is taken very seriously by some, and dismissed just as easily by others – namely the PPC engines whose traffic comes into question. Fraudulent clicks can originate from one of two sources: humans or bots. And fraudulent clicks are typically generated for one of two reasons: to increases revenues from programs such as Google’s AdSense, or to drive up costs for competitors, forcing them out of the PPC market. A report from Search Engine Watch investigates who is really to blame for click fraud, what the search engines are doing about it, and what legal issues are involved.