Unlike search engines, which hunt for Web pages automatically, directories are put together by information specialists who choose reputable sites and arrange them by topic: education, health, politics, and so on.
Some directories are more selective and therefore more useful for scholarly research than the directories that typically accompany a search engine. For example, the directory for the Internet Scout Project was created for a research audience; it includes annotations that are both descriptive and evaluative.
The following directories are especially useful for scholarly research:
Google Scholar http://scholar.google.com
Internet Scout Project http://scout.wisc.edu/Archives
Librarian’s Internet Index http://www.lii.org
Open Directory Project http://www.dmoz.org
WWW Virtual Library http://www.vlib.org