Wolfram Alpha has been launched and is available for the public to try. I sat down to play with it.
FIrstly (using the rare American adverb here - don't be confused), you can't expect Wolfram Alpha to act like Google. It is a new kind of search engine, as one should expect from Stephen Wolfram. Wolfram is famously the inventor of Mathematica and author of A New Kind of Science.
Wolfram Alpha seems to consist of a linguistic interpretation engine coupled to Mathematica and a growing number of databases. Google, on the other hand, is a free-text indexer of Web content. That suggests that while one might be able to type just about any word or phrase into Google that is somewhere on the Web, one must limit Wolfram Alpha queries to concepts that are in its databases or may be treated as mathematical relationships. Indeed, this seems to be the case.
Wolfram's overview video is well worth watching. It, and the example search results available from the home page, give a flavor for the powerful searches one can do with the site.
Following a lead from the video, I tried typing the female name "Bernadette" into the search box. Wolfram Alpha, as advertised, did indeed respond with a presumption that I wanted information about the name and results that included a time distribution plot of popularity. Searching for "Bernadette David" gave me a distribution plot of both names which showed the highest combined popularity did in fact occur around our birth years. Well done, Wolfram Alpha.
Changing the previous search to "Bernadette Peters" resulted in some minor information about the actress and a link to her Wikipedia entry. Wikipedia links are provided where possible, as a transparent but useful attempt to provide flesh to limited source content.
However, more general searches, such as the word "Zepheira", produced no results. Wolfram Alpha responds to null result sets with a message saying "Wolfram|Alpha isn't sure what to do with your input.". That alone makes it clear that Wolfram Alpha and Google are at best complimentary.
Too many users on the site result in a cute message saying "I'm sorry Dave, I'm afraid I can't do that..." - which is only mildly freaky if your name happens to be Dave. The reference naturally comes from the mutiny of the HAL 9000 computer in the film "2001: A Space Odyssey".
Math, science, engineering and finance queries work well, as expected. A Web interface to Mathematica is useful in itself. I suspect that the site will be most effectively used by college students and some working professionals. My mom and dad are unlikely to find it compelling (although my dad is a weather geek and weather data is well represented, so I might be wrong). Still, the lack of detailed weather results such as live RADAR images would more likely lead him to weather.com.
One can do funky and useless math with aplomb. Wolfram Alpha rapidly provided me with the correct interpretation, unit dimensions and unit conversions for the search "100 furlongs per microfortnight", a speed well above that of sound but under that of light.
Minor misspellings were handled effectively (e.g. "area of icosehedron" was correctly interpreted as "area of icosahedron"). Similarly, "volume of icosahedron" resulted in a correct interpretation. I expected the search "distance to a star" to fail miserably, but the answer was surprisingly useful. Try it yourself to see what I mean.
The problem with this kind of interface is that interpretations of intent are notoriously hard, if not impossible, in the general case. How can Wolfram Alpha expect to know that when I typed "birth year of gandhi" that I meant Mahatma Gandhi? What if I meant Indira Gandhi? Guessing is fine as far as it goes, but most search engines chose to give up that approach a decade ago in favor of appendation of search results.
The interface style is also naturally limited by its underlying data. Searching for "the size of the World Wide Web" resulted in a suggested to try "the size of the world wide" - which it could answer as the diameter of Earth.
I wonder how many people recall that Yahoo used to allow mathematical equations in their search engine? They seem to have removed the functionality. One can only presume that they got in the way of becoming a more general Internet search engine. I suspect there is a lesson there for Wolfram Research. Will Wolfram Alpha stay aimed at specialists or will they grow into a more general tool? Time will tell. Their promise to integrate more databases does not promise to address the inherent limitations of guessing linguistic intent.
A growing collection of interesting searches are appearing on http://friendfeed.com/wolfram-alpha.
In summary, Wolfram Alpha is an expert-friendly search system for specialists and is best used as an orthogonal complement to Google and other general search engines. Its approach is pure Wolfram - unashamedly different and unapologetically ignoring of lessons learned by others.