Cover story on Wolfram Alpha; see the full article
To do these sorts of things, it would start with math and science data sets and formulas already held in Mathematica, and build from there. Some of the new information, such as government data on food, would just need minor reorganization. That's what Williams was doing. Other kinds, such as real-time stock data, required licensing. Still others, such as data on aircraft, would be gathered from open Web sources such as Wikipedia and Freebase, and cleaned up--curated.