The Cre8pc Website Promotion site doesn't require doorways because it's designed to be content driven in the first place, for better rank. The sitemap was enhanced in February 2000 to help engines such as Google, which does a fantastic job of crawling pages. Many corporate sites, and popular sites, also don't use doorway pages, but do offer a sitemap. Their advertising dollars and site quality send them traffic, and they're less likely to worry or haggle over search engine rank. Nevertheless, sites that are huge, broader in scope, contain scripting, graphics, are dynamically generated, are Flash sites, etc.
Abuse is to clone the pages.
Say, for example, you use the same design and content on 10 doorways, and despite being tweaked for each engine, there's a good chance they'll all line up in rank on top of each other. Another trick is to buy several domains and clone one site on several domains. This way there's many ways to find the site. This is also cause for penalization by engines AND directory editors are now banning sites that use this practice. Still another is to put redirect tags in a doorway.