Hi... I know Cloacking is black hat technique but what is doorway and hallway pages ? & whats the difference in between three ?
Doorway pages are simple HTML pages that are customized to a few particular keywords or phrases, and they are programmed to be visible only by specific search engines and their spiders. The purpose of these doorway pages is to cheat the search engines to give these sites higher rankings. Hallway pages are also similar to Doorway pages.
If you read the Google webmaster guidelines it will tell you not to use any of these methods. You will get found out very quickly and penalized.