Good god, I get tired of people calling this a "Google killer" when Wolfram has said over and over again that that is not his goal.
That being said, most people who go to Google aren't looking for the kinds of answers Wolfram Alpha provides, so I doubt it will kill google, though if it gets out of Wolfram's control it could begin putting out the kinds of results googlers want.
You never know.
Got to read past the first sentence :)