A subject directory is a database of Internet files which are organized, usually by a human being, into subject categories.
Most directories offer a search engine to query the database.
This popular subject directory has a database of about 500,000 sites. The Virtual Library is the oldest catalog of the web. It is run by a a loose confederation of volunteers who compile pages of key links for particular areas in which they are expert. The Clearinghouse is a non profit venture run by a small group of dedicated individuals. BUBL LINK BUBL is a national information service for the U.K. higher education community.