Cloaking
Showing a search engine spider or bot one version of a Web page and a different version to the end user. Several search engines have explicit rules against unapproved cloaking. Those violating these guidelines may find their pages penalized or banned from a search engine’s index. As for approved cloaking, this generally only happens with search engines that offer a paid inclusion program. Anyone offering cloaking services should be able to demonstrate explicit approval from a search engine for what it is they intend to do, otherwise, this practice falls under Black Hat SEO and brings similar consequences.