If you read "%s Killer" anywhere on a news site, you can safely ignore it.
Agreed that Wolfram Alpha will not kill Wikipedia, but it is unfortunate that some interesting points are associated with such a link-bait title.
Using FaceBook for people searches, Twitter for "what are people saying right now" searches, and Wolfram Alpha for CIA World FactBook searches does demonstrate the potential for vertical search services to thrive in the shadow of Google. If services that are better than Google for some narrow kind of search continue to proliferate, collectively they could become a competitive threat to Google at some point. Or at least threaten some potential Google growth opportunities.
I though Dare made this point rather well, and I think it is worth further discussion.