Searchenginegenie.com

Cloaking is the technique of delivering a particular Web page to a search engine, while serving a completely different Web page to the end user. Search engines commonly overlook - and in some cases even ban - web sites that employ this practice. We are aware of the search engines' views on cloaking and therefore does not employ this unethical technique.

Cloaking is a very old tactic and its total search engine spam. They are not used any more with major search engines. I personally feel cloaking should be avoided totally.