n. A scam in which a web page is a set up with content that places the page high on a search engine's results, but that when visited will redirect the user to a different, usually pornographic, site.
2007
The same is true for the trick known as "doorway scams." This method involves constructing the site so that the content will appear high on the search results. For example, a search on "livestock" may result in a "hit" list with a porn site on bestiality.
2001
In the parlance of techno-speak, a "doorway scam" is an Internet ploy in which an unscrupulous company sets up a Web page to get high level search engine results. When an unsuspecting user clicks on the link, they are then sent to an unrelated (and, usually adult) site.
2000 (earliest)
Sullivan said that 'doorway scams' like those pulled by Nude Celebrity World News aren't at all new. 'They try to put content that appeals to search engines, and then they link to the real site — so they act as the doorway.'