Doorway pages are used mainly to try and get people to your site. The name doorway page is used to describe the page as it acts as a door or storefront to your website. The doorway page is designed using various techniques to try and get it ranked highly within the search engines for a particular keyword or phrase.
Here is an example of a doorway page for this site.
Place your mouse over the images within this page and you will notice that there is tags that pop up. This particular doorway page is created to be optimized for the term "search engine optimization". There are links pointing to my main page that have the words "search engine optimization" in the link, like so:
Links are a big factor in search engine optimization nowadays (see the search engine variables page). As search engines will look at where your links are going, and also how many pages link to you (known as "Link popularity"). Link text is weighted fairly highly in the search engines now.
Another factor is ALT tags (see the search engine variables page). ALT tags are part of the img tag (click here for an explaination of ALT tags). They are also weighed quite highly within the search engines. So it is a good idea to have these tags attached to your images on your webpage. You can add them by putting them into your HTML coding (In green):
<img src="test.gif" alt="this is where the explaination goes">
It's as easy as that. There are many other things that search engines find important. I will cover these later on my search engine variables page. Stay tuned for more information!!