From Jeremy Zawodny's post on the Yahoo Search blog:
- The fundamental idea was to supplement search queries with context. So instead of having to spend a lot of time searching and assembling all the information you're after, this contextual search technology could incorporate that context (the stuff you were reading at you moment you decided that you wanted to know more) to find the most relevant results.
Jeremy points to Reiner Kraft as the primary researcher behind Y!Q. And Reiner has a recent paper, "Mining Anchor Text for Query Refinement" (PDF), that seems related to the techniques behind Y!Q. The paper describes one of several approaches for doing this kind of keyword extraction.