Kules, B., Wilson, M., Schraefel, M., Shneiderman, B. (February 2008), From Keyword Search to Exploration: How Result Visualization Aids Discovery on the Web: "Human computer interaction researchers and web browser designers have developed novel strategies to improve Web search by enabling users to conveniently visualize, manipulate, and organize their Web search results." [abstract][ fulltext, pdf]
My 2 cents: Here is an interesting visualization of optics, graphics, and perceptions in search and results of searches done using tools, such as, PIM (PHLAT), Cha-cha, The Flamenco--interface permits users to navigate by selecting from multiple facets (Materials and Structure Types)--etc. The table of figures is self explanatory: