Directory-based listings are human created categories that list tens of thousands of web sites. Yahoo and Dmoz are categorized as these kinds of search engines. Both are directories but have different qualities that are useful to web site owners.

Yahoo charges a substantial fee for a listing in their directory. However, paying the fee and getting into the Yahoo directory listing could bring you good traffic.

Dmoz was developed and is maintained by volunteers. It is funded by donations and submissions are free. There are very specific rules that apply to getting into the Dmoz directory. And, since it is human edited and those editors are swamped with requests for inclusion, you may have to wait up to a year for inclusion. Dozens of smaller directories get their information from Dmoz.