What you think about, if directory have subject appropriate one keyword. I find business directory worldbusiness.in. This site dedicate one word at all: "business". How much such directory useful for me, if "business" is keyword for my site. Thank you for attention.
If that site is about business, it would benefit your site more than other general directory since these two sites are related. however, it is hard to say how much, you have to check the PR, #link on page, if links has no follow tag etc etc.. anyway, a business directory will be better than a genearl one
Subject directories, such as http://worldbusiness.in really useful for promote my site, if my keywords equal subject of this directory?
Do you consider that subject directory where subject is one keyword useful for SEO? On http://worldbusiness.in submission text links and articles is free.