Once in, you have access to much of the site, including UK job ads and conference notifications. The Archive of back issues is available only to subscribers to the print edition. Lists are compiled by teams of people, who visit sites whose authors have submitted them for indexing, and then make a decision on whether to include the site and where in the classification system it belongs. Robots have the advantage of thoroughness and speed, visiting more sites and indexing them faster than any human team could. Lists have the advantage of being based not only on the occurrence of key words, as with robot queries, but on an intelligent grasp of conceptual categories and the often complex and multiple interrelationships among them.
Some sites combine features of both robot and list.
Hope Tillman's Evaluating Quality on the Net includes a section on evaluating the results of search engines, and the different procedures each uses. AltaVista One of the fastest and most comprehensive of all the robot search engines. ANZwers search engine Focuses on Australian and New Zealand sites. Ask Jeeves Provides plain English searching. Submit a plain English question, and the machine will parse it, recognise some of the basic categories to which the terms belong, suggest further questions where relevant, and tell you how many matches were found with these terms and categories on several of the main search engines.