| Search Engines Use computer programs to search the web. | Metasearch Engines Search across several search engines. | Subject Directories Selected by people. |
| Ask | Librarian's Index to the web | |
| Lycos | Dogpile | The Internet Public Library |
| Alta Vista | Yahoo! | Evaluating Web Sites |
| HotBot | Metacrawler | World Wide Web Research Tools |
| Vivisimo | Awesome Library | |
| Subject Search Engines | Metasearch | |
| Scirus (science) | ||
| SearchEric (education) | ||
| SOSIG (social science) | ||
| HUMBUL (humanities) | ||
| PSIgate (physical science) | ||
| GEOSource (geography & environment) | ||
| Peter's PolySearch Engines (dictionairies, biographies, reference) |