AdSense ~Abuse

Some webmasters create sites tailored to lure searchers from Google and other engines onto their AdSense site to make money from clicks. These "zombie" sites often contain nothing but a large amount of interconnected, automated content (e.g.: A directory with content from the Open Directory Project, or scraper sites relying on RSS feeds for content). Possibly the most popular form of such "AdSense farms" are splogs ("spam blogs"), which are centered around known high-paying keywords. Many of these sites use content from other web sites, such as Wikipedia, to attract visitors. These and related approaches are considered to be search engine spam and can be reported to Google.

There have also been reports of Trojans engineered to produce fake Google ads that are formatted to look like legitimate ones. The Trojan Horse apparently downloads itself onto an unsuspecting computer through a web page and then replaces the original ads with its own set of malicious ads.