Excerpt on it, for full article hit link.
Instead of serving up a list of popular links to other sites that contain the search term picked by a user, Alpha is a more-or-less closed system. It tries to dissect a question into its components and then performs calculations, using its own source materials, to compute an answer. The results are presented as a sleek collage of tables, charts and graphics. Alpha, in short, acts like a nerdy reference librarian who is equipped with the latest calculators and endless stacks of books and encyclopedias. Hit upon the right subject and it will excel at calculating airflow around a surface, showing the distribution patterns for DNA base pairs in human genes, spitting out prime numbers or computing and comparing crucial statistics for various national economies. Yet simple queries such as “climate change” or “Gordon Brown” will yield the equivalent of an empty stare.
http://www.economist.com/science/displaystory.cfm?story_id=13643997