Wolfram Alpha is not a search engine.

In a talk at Harvard Law School, Stephen Wolfram, a well-known mathematician, scientist and entrepreneur, gave a demonstration of his soon-to-be released Web service which promises to answer all sorts of questions. The service, called Wolfram Alpha, had technology bloggers abuzz that a rival to Google was about to hit the Web.

While search engines like Google, by and large, find things that already exist on the Internet — Web sites, photos, videos, blogs — Wolfram Alpha answers questions, often by doing complex, and new computations.

It’s hard to judge a product from a demo, but by the looks of it, Wolfram Alpha is impressive.

What can it do? It can describe places, like Lexington, Mass., by its vital statistics, such as location, population, weather, etc. It can compare Lexington with Moscow. If you type “LDL 180,” it will tell you the percentile of the population with higher or lower cholesterol and show you the answer on a chart. If you tell “LDL 180 male 45,” it will adjust the chart for gender and age group. It can chart the life expectancy of a male age 40 in Italy or tell you who was president of Brazil in 1928.

There was a lot more, but it was hard to make out on a choppy Webcast, where the video kept cutting out. (For those interested in watching the presentation, a replay of the Web cast will be available soon on the Berkman’s Center site.)

But Jonathan Zittrain, a law professor at Harvard and the co-founder of the Berkman Center for Internet and Society, who organized Mr. Wolfram’s talk described the service as a powerful “computable almanac.”

“It aspires to the depth and breadth of a traditional almanac,” Mr. Zittrain said. “And it allows people to juxtapose data, to take a set of facts and relate them to other facts in new ways. You can compare population trends to the amount of fish consumed and correlate it to mortality rate.”

Mr. Wolfram said the service is built on four pillars: a massive amount of data, that his company has collected from various sources; a computational engine built on top of Mathematica, one of Mr. Wolfram’s prior inventions; a system for understanding queries; and technology to display results in interesting ways.

Mr. Wolfram said the project was still in its early stages but was mature enough to begin making it available to users, something his company, Wolfram Research, plans to do next month.

While Wolfram Alpha is not a Web search engine, it is possible it will compete with Google or other existing services like Wikipedia, for certain kinds of questions. Incidentally, in the middle of Mr. Wolfram’s presentation, Google announced a new search feature that makes it easy to find and compare data from public sources like the Census Bureau and the Bureau of Labor Statistics.