Is this URL ok?

http://www.yourdomain.com/blue_widgets/index.html

[adam_ant]

I was reading a tutorial and i came across this, what do you think?

Page Name

Now choose a page name for your doorway page. I generally use the main keyword to start with then rename the page later. However here's a major tip for you. You will gain an edge by naming your page 'index.html and uploading it to a subdirectory named after your targeted keywords.

For example if your keyword phrase was "Blue widgets" then your doorway page URL should look something like this:

[yourdomain.com...]

Use an underscore to separate your keywords.

[Macro]

There used to be an advantage in having a folder name based on keywords. Most webmasters don't believe that applies anymore. I don't think you'll see any advantage.

If you are using keywords in file names or folder name it is considered better to use a hypen than an underscore. No factual data to back that up, but it seems to be what the more experienced webmasters here prefer.

By doorway pages if you mean non-content pages stuffed with keywords and posted purely to fool search engines... my advice would be to avoid it like the plague.

And welcome to WW :-)