This is an unethical practice followed by some site owners which involves hiding your true content from search engines by showing one type of content to them and another entirely different type of content to the end user. These two different forms of your page are condemned by search engines and strict rules have been put in place to discourage site owners from indulging in this practice. Those who are found guilty of violating these rules may end up having their pages banned from search engines. However, there is a form of cloaking called approved cloaking which is only possible with search engines that allow for a paid inclusion program, as per which the site owner must get approval first by explaining effectively what their intentions are behind such a move.