Directories normally provide lists of web pages arranged by subject. These lists are compiled by a human being who uses standards to determine what web pages should be included. Search engines allow you to search by keyword.
Many search engines are databases that are compiled by a computer program.
The computer program collects information about the web pages included, but does not evaluate them. Many web searching sites include both a Directory and a Search Engine. Argus Clearinghouse Provides topical guides which identify, describe, and evaluate Internet-based information resources. A catalog of selected internet resources covering all academic subject areas and cataloged according to the Dewey Decimal Classification. It includes databases, electronic journals, electronic books, bulletin boards, listservs, online library catalogs, articles, and directories of researchers, among other information.