Doorway pages are web pages that are created to rank high in search engine results for particular phrases with the purpose of sending you to a different page. They are also known as landing pages, bridge pages, portal pages, zebra pages, jump pages, gateway pages, entry pages and by other names.
If you click through to a typical doorway page from a search engine result page, in most cases you will be redirected with a fast META refresh command to another page. Doorway pages are easy to identify in that they have been designed primarily for search engines, not for human beings. Sometimes a doorway page is copied from another high ranking page, but this is likely to cause the search engine to detect the page as a duplicate and exclude it from the search engine listings Unless you are using the TrafficBoosterPro Doorway Generator Script that create unique content pages. The RSS Feeds are Targeted and selected by you, they do not show any URL's (so you don't leak page rank) and they are selected randomly from files on your server by mix up 3 or 4 or more RSS Feeds each time so that the content will not be repeated to any other pages, that way will not let the search engine to detect the page as a duplicate and doesn't penalize your site.
Because many search engines give you a penalty for using the META refresh command, some doorway pages just trick you into clicking on a link to get you to the desired destination page.
The new era of Doorway pages is come with the RSS Feeds technology. A new software named TrafficBoosterPro is fetching RSS Feeds from the Internet that are optimized on your keywords and produces thousands of doorway pages that are using keyword staffing and Cloaking technique to show the engines new fresh content at every visit because RSS Feeds are updated almost every 15 minutes and it's also fetching the RSS Feeds of 3 or more sites at the same time randomly to confuse the engines not to find the same content to other sites and ban the doorway pages domain. When a visitor arrives at any of these pages it redirected by JavaScript method that search engines can't trace and sent the visitor to the desired site. (Source Wikipedia)