(WAIS) A distributed information retrieval system. WAIS is supported by Apple Computer, Thinking Machines and Dow Jones. Clients are able to retrieve documents using keywords. The search returns a list of documents, ranked according to the frequency of occurrence of the keyword(s) used in the search. The client can retrieve text or multimedia documents stored on the server. WAIS offers simple natural language input, indexed searching for fast retrieval, and a "relevance feedback" mechanism which allows the results of initial searches to influence future searches. It uses the ANSI Z39.50 service. Public domain implementations are available. Other information retrieval systems include archie, Gopher, Prospero, and web.