Doorway Pages
Doorway Pages (or Landing Pages which is newer terminology for Doorway Pages) do not help rankings over a long period of time, and can lead to your site being penalised.
Doorway Pages were an old method used to create a particular page heavily optimised with certain key words/phrases. These pages were the “doorway” into your website, which in many cases were invisible to the viewer of your website, but visible to the search engines. Once Google became a major player in the search engine market this methodology slowly started to phase out as the search engine community realised that Doorway Pages were not endorsed by the major search engines and could in fact lead to a website being severely penalised, or in some instances banned altogether from their listings.
Some SEO companies still use this method, which is why it is important that you find out what methodology your SEO will use to optimise your website. You may get fast results initially through operating this way, but if you are interested in long term success it is important to use ethical methods to achieve these results. If a website is optimised properly then there is no need to use these types of tactics; it will simply mean that high rankings will take a little longer to achieve. The advantage of this is that those “ethical” rankings will be long lasting.
If in doubt about the methods a particular SEO is using, do some research to clarify whether these methods are ethical or not.
Below are some links to articles relating to unethical SEO methods that have had very negative effects to some businesses websites:
http://www.isedb.com/news/article/953