Cloaking

From Search Engine SEO SEM

Cloaking is a technique in which the content presented to the search engine spider is different to that presented to the visitor's browser. This is done by delivering content based on the IP addresses or the User-Agent HTTP header of the user requesting the page. When a visitor is identified as a search engine spider, a server-side script delivers a different version of the web page, one that contains content not present on the visible page. The purpose of cloaking is to deceive search engines so they display the page when it would not otherwise be displayed.