Another technique to avoid is called "doorway page".

Doorway pages are web pages that are created for spamdexing, that is to spam the index of the search engine by sending the search engine with spamming keywords, but serving the endusers with different page. This technique is combined with the use of cloaking method we mentioned above.

Some webmasters use some basic technique like meta refresh, javascript, even some coding (PHP, Perl etc.) redirection to serve the doorway page before sending the real page. And the most used doorway page are those pages with high rank in the search results, so they want to cheat the search engine that their content are of high rank.

But some doorway pages are easily to be spotted out as the search engine regards the content as duplicated and removed from the index.