WhatSubject directories are listings of Web sites compiled either by volunteers or paid staff who list and categorize them. These directories do not attempt to categorize the entire Web, but merely offer access to what each directory considers important or the best Web sites. It is important that the searcher be aware of the selection policies and/or any bias employed at each directory. Who is making the selection of Web sites and how is it determined which Web sites to include?
HowSubject Directories can be divided into a number of different categories by type:
1 - Academic or professional directories
These are compiled and maintained librarians, subject experts and professionals in the fields they oversee. They are designed to be collections of the best and most authoritative Web sites in a field.
2 - The Commercial Subject Directory
Designed to appeal to the searching public and needs to garner traffic in order to be profitable, they use professional reviewers to organize the Web for you.
3 - Directories compiled by net citizens
Here, the average hobbyist or individual with a particular interest volunteers his/her time "helping the Internet organize itself." The Open Directory Project is an example of this type.