A page made specifically to rank well in search engines for particular keywords, serving as an entry point through which visitors pass to the main content.
In practice, usage of doorway pages varies considerably, and there are countless other terms used to describe them. The pages themselves range from unique, content-rich pages to generic, keyword-stuffed pages.
Doorway pages have acquired something of a bad reputation due to the frequent use (and abuse) of doorways in spamming the search engines. The most flagrant abuses include mass production of machine-generated pages with only minor variations, sometimes using re-direction or cloaking so the visitor does not see the actual page requested. Doorways used in this manner add to the clutter that search engines and Web searchers must contend with.
Critics of doorway pages contend that the time & effort spent generating pages would be better spent optimizing pages that are integrated into the content of the Web site, plus producing more content to attract repeat visitors.
A wide range of opinions exists concerning what constitutes a doorway page and when they are acceptable. One of the most common justifications is for sites which have database-driven content that would otherwise be invisible to the search engines.
Some would argue that every single page on a Web site is a doorway. Perhaps, but then the term “doorway page” would lack any distinct meaning, with no term to describe the pages that are created specifically for the search engines.
see also: SEO Tools