Google as a hidden link detection tool
In hope to make their doorway pages rank better in search engines, spammers search for compromised web sites and use various security holes to insert hundreds of hidden spam links into trusted web pages.
While the parasites are hidden from human web surfers, they are visible to Google and other search engines. So, simple google searches can reveal thousands of infected web sites.
Here are the lists of google searches tailored specifically to find infected web pages: