Google has now achieved the level of 'Hoover' where the trade name has been transformed into the noun or verb. As a result, we pretty much take for granted how a web search engine works. We type in the search term and generally receive a ranked list of web page links.
WolframAlpha is a 'computational knowledge engine' that is designed to "make all systematic knowledge immediately computable and accessible to everyone". The goal is explained in a bit more detail as "to accept completely free-form input, and to serve as a knowledge engine that generates powerful results and presents them with maximum clarity."
In a sense something like Wikipedia provides answers rather than a list of pages, and Google itself can provide specific information – try typing in the search term: 'convert 50 litres to gallons' for example. One of the areas where WolframAlpha can do more is in comparisons – in the example above, we've typed the following into Google and then into WolframAlpha:
Rbs Lloyds Barclays
Whereas Google returns a list of websites for us to choose and conduct our own research, WolframAlpha delivers much more targeted information on the financial results of the companies. The tables of data and the charts are interactive, allowing you to choose different periods and different chart styles. There is also an experimental feature that allows you to download your results as a PDF.
Although WolframAlpha is in the very early stages of its development, it's worth having a look at how it works to see what a search engine based on mathematics and computation can do.