What is doorway pages how it is created and what it's importance in our website. Are it is important if your site have flash.
Doorway pages are a type of web page created exclusively to gain popularity with a specific search engine. They are also referred to as bridges, gateways, and entry pages. They are a matter of contention within the search-engine optimization world, with some holding that their use is both immoral and ultimately counter-productive, and others believing they are a sure-fire way to achieve consistently high rankings.
You'd be better off with a landing page or a squeeze page where you can get visitors to opt-in for your mailing list.
I will sum it short here - Doorways page is an old fashioned way of Blackhat SEO. Those pages are generated for bots and keyword only purpose. These kind of pages would be effected for bots but not common visitors. When the search engine bots come to the page - they will see the page has a good content for specific keyword and give a good rank for that page, while common visitors will be redirected to a real website that has content almost completely different from the content in doorways page.