The Web World Directory seems to be a cross between a general website directory and a business directory. Their top level categories include the general categories you would find in most other general website directories. These include arts, education, health, kids, news, reference, and science.
However, two of their top level categories are those you'd normally find only in business directories. These are USA lodging and USA real estate. I suspect this has more to do with their catering to the types of businesses that are more willing to pay to be listed in directories rather than improving the user experience or any other reason.
The homepage of this directory is attractive and clean, making it easy to see what it has to offer. There are no ads on the homepage. However, a significant number of ads are placed on all other pages, in some cases deceptively placed so that advertising look like directory listings.
Another problem is that the basic navigation menu moves from an obvious place at the top of the homepage to the bottom of the inner pages. This makes it a little difficult to immediately find basic links like "submit a site" and "contact us" if you initially land on any other page besides the homepage.
The Web World Directory's submission guidelines are much more thorough than you find on many general directory sites. For example, they do not accept any sites that do not list contact information on the site. Furthermore, the contact email that is submitted with the submit a site form must also be found on the website.
While they do allow site owners to submit their own website descriptions, they do not allow promotional language to be used. Plus, they specifically state that words like "best," "coolest," "cheapest," and "#1" are not allowed. This is a good sign because, as a general rule, the stricter the submission guidelines the higher quality the directory and the fewer links out to bad neighborhoods (essentially spam sites and/or sites that lack useful content).
Therefore, if your site is listed in the Web World Directory, it should count as a positive link in the eyes of Google, Bing, and other search engines.
The biggest concern I have about the Web World Directory is the fact that they offer a 25% - 55% discount on bulk submissions from search engine optimization (SEO) companies and search engine marketing (SEM) companies. Plus, added to this, they don't just accept top level domains but also subdomains and even internal individual website pages.
You may also get some sites like about.com and webmd.com that can afford it over-represented in the directory with subdomains like <em>men.webmd.com and http://nutrition.about.com</em>. Plus, you find individual pages listed like <em>omega-3-fish-oil-wonders.com/fish-oil-benefits.html</em> listed when in most directories you would only have the main domain listed.
The Web World Directory was established in 2001. This makes it one of the older directories and at least fairly successful. They charge a one time $25 fee to have a site reviewed and considered for a permanent listing (assuming your site doesn't violate their submission guidelines in the future) with no recurring fees. They do not guarantee a listing and they do not refund your money if your site does not meet their submission requirements so be sure you read those carefully before paying.
They do offer free consideration for listings in the regional categories but they must be top level domains. No other free reviews are offered.
I would recommend adding this directory to your "B" list of potential directories to list in, primarily because of the maturity of the directory and it's relatively strict submission guidelines.