SEO Earnings

Cloaking is a general SEO technique in which it presents the content to users and search engines differently. This is done by delivery different content based on the IP adresses or the user agent in the HTTP header, for example, Google crawler presents as googlebot when it crawls your site.

So some webmasters create two versions of page, one is for the enduser and one is for the search engines. but some search engines, like Google, regards this kind of technique as dirty trick to cheat their search engine for high ranking. For this reason some search engines threaten to ban sites using cloaking.