A Web site set up for search engine spiders rather than humans. Shadow domains are indexed by the search engines just like all other sites on the Web, except the shadow domain is not for human visitors, and its content would look like gibberish. Pages are loaded with extra keywords that make the page look like top-notch content to the spider and help rank the page higher in the search results. Also called a "cloaked" site, the pages are known as "phantom pages."

The key to an effective shadow domain is the ability to redirect a human to the real Web page upon arriving on the phantom page, while letting the search engine spider scan the page.

Create a Shadow Domain Automatically
There are programs that create shadow domains automatically, such as the very comprehensive shadowMaker from fantomaster.com GmbH (www.fantomaster.com). ShadowMaker generates self-contained, independent Web sites for its customers with sophisticated scripts that differentiate people from spiders and redirect bona fide users. The scripts use a spider database that contains the spider's IP address and attributes, and fantomaster.com updates the database several times daily.

Hundreds and Thousands of Sites
Search engine ranking is a numbers game, and Webmasters can create hundreds of shadow domain sites, all hosted separately that flood the search engines with thousands of phantom pages. This method is especially popular in highly competitive fields such as finance, pharmaceutical drugs, gambling and adult content. See cloaking and spider.