A search and a browse on a single user query is performed. A refined query is selected from the results of the first user query. Thereafter, a list of concepts from a first directory associated with the refined query is obtained. The concepts are defined in a hierarchical relationship with concepts having broader scope being higher in the hierarchy and concepts having a narrower scope being lower in the hierarchy. Additionally, a list of web sites associated with the search concept is obtained from a second directory.
Goes into how their refine or broaden the search works. How their results are laid out. How all of their category systems works.
Basically what is listed in here is a lot of what you are seeing on MSN search now. Its a good read.