Hallway pages are sometimes used to manipulate search engines. These specific pages were not written for users, but only for the automatic search programs of a search engine (crawler). Hallway pages do not contain any relevant user information. Instead, they mainly or exclusively consist of a list of outbound links to other webpages of their operators that have already been optimized for the search engines. Such highly optimized doorway pages direct users to the sites requested by the operator, for example, sales pages.
Crawlers are supposed to detect the links on a hallway page quickly and include them in the index of the search engines. Much like they do with regular sitemaps that also list a collection of links. Hallway pages do not inform about the structure of a particular website, however. Their purpose is to make search engines aware of links to several doorway pages. With this method, operators expect a better ranking of their marketing-relevant pages. Because their actual sales pages are usually not ranked very high on the SERPs.
Hallway pages are indeed not invisible to users, but their main purpose is to attract users to doorway pages. From there, users will then be redirected to sales pages, sometimes even without their own doing.
Hallway pages do not serve the interests of users. Their sole purpose is to help webmasters promote sales. The use of hallway pages contradicts Google’s Quality Guidelines for webmasters and is deemed an unethical marketing strategy or black hat SEO.
As a general rule, hallway pages are also not recommended because the expected advertising effect will likely not occur. The search engines have invested a lot in their development in order to accurately detect such breaches of their guidelines reliably. If the use of such hallway pages is recognized by the search engine, the operator concerned may be penalized by reduced ranking or removal from the index. Anyone offering hallway pages as a service will be ruled out as a professional service provider of online marketing.