Ben Edelman's False and Deceptive Pay-Per-Click Ads analysis looks at specific ads on Google.com that seem to violate Google's editorial guidelines and perhaps US laws over "free" services being offered.
Edelman reviews ads that use the words "free" or make other claims that are said to be false.
He looks at "charging for software that's actually free" here, then he looks at "the "completely free" ringtones that aren't" here, and then reviews some "ads impersonating famous and well-known sites" here.
Finally, Edelman reviews the law, ethics, and incentives Google is faced with specific to these ads. He views Google and the search companies as the ones that really profit from such ads and suggests that Google "expand the policy to prevent these scams."