There is often a lot of confusion around what a doorway page is and since it is specifically against Google's very own guidelines, it is important to understand that you do not make pages that look and feel like doorway pages. Google's own guideliens define them as:
Doorways are sites or pages created to rank highly for specific search queries. They are bad for users because they can lead to multiple similar pages in user search results, where each result ends up taking the user to essentially the same destination. They can also lead users to intermediate pages that are not as useful as the final destination.
They then give these three examples:
- Having multiple domain names or pages targeted at specific regions or cities that funnel users to one page
- Pages generated to funnel visitors into the actual usable or relevant portion of your site(s)
- Substantially similar pages that are closer to search results than a clearly defined, browseable hierarchy
But John Mueller from Google answered it on video and his explanation will probably be more clearer to you. In short, a doorway page is many pages designed to try to rank for many keyword variations and permutations.
At the 2 minute 9 second mark, John Mueller defined doorway pages as:
Well, a doorway page would be if you have a large collection of pages where you're just like tweaking the keywords on those pages for that.If you have one page that links out to a bunch of other pages and that's I don't know just like a kind of a sitemap page something like that.
I think if you focus on like a clear purpose for the page that's outside of just I want to rank for this specific variation of the keyword then that's that's usually something that leads to a reasonable result. Whereas if you're just taking a list of keywords and saying I need to make pages for each of these keywords and each of the permutations that might be for like two or three of those keywords then that's just creating pages for the sake of keywords which is essentially what we look at as a doorway.
Here is the video embed:
Hopefully this clarifies things a bit for more of you.
Forum discussion at YouTube.