Cloak pages display Web page content differently to search engine spiders than to humans in order to achieve higher rankings in search engine results.
It's a page with more keywords on a subject(according to the web page or the content of the page) tend to rank higher than those with fewer keywords, but excessive repetition of a word makes the Web page look unskilled.
According to the search engine guidelines any type of cloaking is bad, are there cases where cloaking might be legitimate. Cloaking is often considered a Black Hat technique, because it tries to trick search engines into giving the site a higher ranking than it normally should. Actually this subject is very controversial and SEO experts continue to debate about when cloaking might be acceptable and when it is not. It's depends on those who already used this and had the results whatever it's bad or good.
At last I say that any type of technique which is called or related to the Black Hat technique shouldn't use for SEO, may it gives us better result but always we have to try so called White Hat technique.