Doorway pages are single page websites used as a funnel-point to attract visitors from search engines. Some search engine optimization (SEO) companies create these doorway pages, then optimize them to perform well in Google and other search engines. The problem is that they are typically cookie-cutter pages that aren’t attractive, and more importantly, don’t support the branding of your company. Doorway pages are a lazy excuse for SEO. Instead, why not optimize the site (page by page) to attract visitors, extend the brand, and provide substantive information to potential clients. This is a much better solution than paying a monthly fee for a single page that offers nothing more than a generic look, a paragraph about the company, and some contact info. Do you really think this will impress visitors into calling? After all, the goal is to have the visitor click-through to the real site anyway. A doorway page may be the first thing a potential client sees when learning about a company. And they don’t make a good first impression.
Google says “…doorway pages tend to frustrate users, and are in violation of our webmaster guidelines.” (link to source)