Wolfram Alpha is like a cross between a research library, a graphing calculator, and a search engine. But does Wolfram Research's "computational knowledge engine," set to debut publicly later this month, live up to its hype as a Web site that Google needs to be afraid of? Wolfram Alpha creator Stephen Wolfram on Tuesday gave a demo of the service to a crowd of online reporters. Few have access to the private test version of the service itself, but we got access Monday night. We found it compelling, if limited. We're eager to see this site develop. It does things with online information that Google does not. Here are our impressions of the current version of Wolfram Alpha.