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cloaking

Cloaking

伪装

websites appear at search engine cache 
are different from the browser view

or 

bots view are different then users view

呈现在搜寻引擎
的内容与您显示给使用者的内容不同，
这些行为我们一般称为「伪装」(cloaking)。

often been used by setting user_agent with
different usarage.....

user_agent is one of HTTP headers
and one of ServerVariables

---------------attention------------------
it is danger to use Cloaking skills to cheat search engines

major search engines may too buzy to recheck cloaking

but it is soon.... that they may easy to create type2 bots 
without their bots names on when CPU become
faster than now.

Google began to warn all websites since 2006.
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