Are the major search sites worried about Wolfram Alpha? No, and yes. They have talked often about how online searches are good for finding information -- reliable or otherwise -- that others have posted, but not so great at answering questions themselves.
Microsoft's new Bing.com is billed as something more than basic search. Yahoo has modified its search algorithms.
And if you go to Google, you'll see they've been restless too. Enter "square root of 41," you will get 1.1 million links -- but the first thing you'll get is a calculated answer, much like Wolfram's:
"Square root(41) = 6.40312424."