PPC is a loser. About the only rationale for using it is for hot items such as concert tickets and other time-sensitive/impulsive buying.

Most fraudulent click-throughs come not from AdSense, but AdWords. Why? Because to fraudulently use your own site to "pay yourself", as some put it, is a quick way to get booted. The search engines are not interested in paying anyone. They are interested in collecting, from both ends. Period. It is also much easier to fraudulently click on sites that are targeting "your" keywords.

Also, why would anyone throw money into Google's Adsense or AdWords PPC when they already hold top spots in Google's "natural" redults? What someone isn't telling you is that they have over 6,000 sites linking to them. Their PPC campaign with Overture simply gets the site into the directory to be indexed by search engines, but not ranked.

It is doubful that they would lose any sales by abandoning the PPC campaign. This in turn would increase their ROI, because they would no longer be throwing away their money.

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DrTandem's San Diego Web Page Design, drtandem.com