A doorway page is something used in Black Hat SEO for spamdexing purposes.This is when webmasters or SEO agencies attempt to manipulate search results by spamming the indexing process.Using doorway pages involves inserting keyword phrases that achieve high search volume while sending browsers to another page when they find the result and click the link.

Cloaking is when a webmaster or SEO deliberately shows a different version of a webpage to a search spider and a human user.It is also used alongside doorway pages to redirect browsers without them realising.Cloaking involves the use of server side scripts so pages know whether a search spider or a human is visiting them.