Most search engines take the search terms and check for documents in which they are matched.
Advanced search' with its customary multiple input windows, drop-down menu selection of operators for combining search terms and specifying other parameters, may not offer the slickest of interfaces, but it provides a degree of control over the search which many users value. These methods would never make it in an ease of use' honours list, but in reality, they are usually used by people who like to use them, e.g. librarians. Comprehensiveness Many of the well-established search services index hundreds of millions of Web documents. Generally they index the full text of documents. None index anything like all the information on the WWW, and as Web information increases, the proportion indexed decreases rather than increases.