Using Doorway Pages & Keywords
Doorway pages have been developed to position high for a specific keyword or phrase. Don't try to hide these pages on your site so that surfers should not see. Instead think of every page on your site as a Doorway, or Salesman for your website.
If you sell more than one widget & most do, it is impossible for you to optimize one page to cover all 150 widgets. However, by creating doorway pages you can create entry pages to your site which spotlight on keyword & phrases for their specific widget.
Components of a Doorway Page
A doorway page contains all of the elements associated with any other web page. The only difference is that the title, keywords, description, and body content have all been optimized for one or two specific keywords or keyword phrases for your green widget.
Usually, however, doorway pages don't contain fancy layouts. Keep it simple. File sizes should be kept low - 60K and below. You want your page to rank well with the search engines not be a work of genius. Text is what the search engines are looking for so give it to them.
The Debate
Some webmasters like them some don't. My main complaint with doorway pages is that I usually can't find anything worth reading. What is the use for making pages that no one reads? Content is king! But remember to write compelling text to sell your widgets and keep the main design layout the same as your website.