Set Your Mind

Yahoo! is testing its new Yahoo! Mindset Search Engine, which promises to be an "Intent-Driven Search". Based on your intent of "shopping" or "researching" it dynamically rearranges the search results for a particular keyword.

From the home page,

A Yahoo! Research demo that applies a new twist on search that uses machine learning technology to give you a choice: View Yahoo! Search results sorted according to whether they are more commercial or more informational (i.e., from academic, non-commercial, or research-oriented sources).