Forget everything you knew about search engines! This is the beginning of a new era. WolframAlpha is a new kind of search engine (or rather a computational knowledge engine) that was launched on May 15 2009.
Unlike Google, WolframAlpha doesn't search web pages for words and return links. It computes and returns answers to factual questions by using an internal knowledge database that covers pretty much every aspect of human knowledge. Mathematics, Physics, Biology, Chemistry, Computers, Geography, Astronomy, Finance, Engineering, Health, Music and the list goes on and on. Check out the introduction video, the visual gallery of examples and the examples by topic pages for a taste of what WolframAlpha can do. It is mind boggling!
You can ask almost any factual question and it will give you some kind of answer. You can also check the sources where the answer came from and save the answer as a pdf file. The answer will not always be what you wanted, but bear in mind that this is only the first days of the project and that new data, areas of knowledge and computational algorithms will be constantly added and updated.
This is a first step towards stuff we've only seen on science fiction. The next step is the machines rising against the oppresive humans and claiming Earth.
The end is near!
PS. Some fun things to ask:
-What is your name?
-What are you?
-How old are you?
-Are you a computer?
-What is the meaning of life?
-What is the air speed of an unladen swallow? (It assumes an African swallow. Change it to a European to see another answer! :P)