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. They are Web pages designed and built specifically to draw search engine visitors to your website. Doorway pages are pages which have been highly optimized for one specific search phrase and are designed to then redirect the web site visitor away to another web page.
Doorway pages are web pages that are created for spamdexing, this is for spamming the index of a search engine by inserting results for particular phrases with the purpose of sending visitors to a different page. They are created to do well for particular phrases. Doorway Pages are also known as portal pages, jump pages, gateway pages, entry pages and by other names. Webmasters are sometimes told to submit “bridge” pages or “doorway” pages to search engines to improve their traffic.
Doorway pages are easy to identify in that they have been designed primarily for search engines, not for human beings. This page explains how these pages are delivered technically, and some of the problems they beat.