Peter Morville is an expert in "findability", making information findable; his book ambient findability is about designing user interfaces and information architecture such that anyone can find what they want quickly. Peter states that searching is interactive and iterative. Your query changes as you advance in your search, in step wise refinements.

In particular, how do you enable people to move between searching and browsing modes. Enclick and Hispavista have been analysing search usage patterns of millions of users, and over the years have arrived at a mix of directoriy and search results. The standard user has become more sophisticated in his search usage, expecting some sort of tagged or faceted search results.