This is the latest search engine (is that even the right phrase? Wolfram Alpha themselves call it a "computational knowledge engine") that is sweeping the web this month
It isn't even live yet, but the high digirati have seen demos and are very excited. If you were at the FLA Conference you heard Richard Maddaus mention it.
It sounds as though it could be good for data and number crunching questions, but I always remember one of my ultimate reference questions, "How long was Christ's ministry?" I will enjoy seeingwhat it does with that.