Contextual Search

Y!Q is one major approach to contextual search. It's developer is calling it distruptive distribution, and Yahoo is starting to thread it through their products. Like much of Yahoo's approach to searching and the web, Y!Q's implmentation relies more upon people distributing it across the web rather than having a pure algorithm doing all the heavy lifting like most of Google's products. If Microsoft had a viable approach they would probably side with Google on the pure algorithm approach, but then they don't give away their products for free and would therefore have a tough time catching up to either Yahoo or Google in this space.