clipped from www.seochat.com

A Different Way to Search - Query reprocessing

This approach, implemented by sites such as Hakia and Powerset (recently purchased by Microsoft), attempts to subject search queries to logical analysis in order to better determine the intentions of the searcher.

Categorization

This is the subdivision and display of short - often single-word - queries in categorized form to help the searcher distinguish between various interpretations of the search.

Parallelism
This feature enables certain terms in the search query to be dynamically replaced with others that have the same meaning in order to expand the result set. Hakia provide the example of "cure" replacing "treat" in a health query

Generalization
A typical search engine query contains general terms that if treated literally artificially limit the result set. Hakia's generalization function will show results, for example, that contain the names of specific car manufacturers in response to a query that contains the word "car."