The much-heralded Wolfram Alpha computational knowledge engine has finally launched. Feedback about the site is largely positive, although some users have expressed frustration with persistent deficiencies.

The site differs from a regular search engine in that it processes queries to return the actual answers, instead of returning a list of web pages that may contain the result.

Wolfram Alpha's creator, British-born Stephen Wolfram, has claimed that, thanks to "algorithms and heuristics, lots of linguistic discovery and linguistic curation, and some serious theoretical breakthroughs", the tool is able to understand even complex human language to provide the correct answer.

However, one disgruntled user wrote on the Wolfram Alpha blog that the site is failing on accessibility and usability, as prescribed by Web Content Accessibility Guidelines.

"One of the keys to Google's or Wikipedia's success is accessibility," the user wrote. "I love the results of the machine, but please get to web standards! Use XHTML, MathML, XML with Stylesheets and SVG/Canvas Object for results rendering. Rendered text [and] images are so 1997."

Another user complained that pages do not display properly in Internet Explorer 6, while a third said that the site is "promising but maddeningly incomplete".

"Wolfram Alpha provides some excellent extensions to a search engine and, for some queries, is already better (it seems) than Google," the user wrote. "It is better in the sense that when it 'wins' it presents an exhaustive answer, complete with calculations if appropriate and without all the noise found on Google. However, for most queries it comes up empty."

Feedback on the blog appears positive in the main, and many are heralding the site as the "future of search".

When vnunet.com tried the engine with 'how many swine flu deaths?', it returned an answer without any problems, offering a list of background sources and references.

The engine even managed to have a stab at the more difficult question, 'how many fish in the sea?', estimating a total of 2x10^9 metric tonnes, and detailing its calculations.

Elsewhere, it had difficulty understanding the language we used in our search queries.

'How many UK people own a mobile phone?' was met with the stock response: 'Wolfram Alpha isn't sure what to do with your input'. Dropping 'own a' from the search phrase returned an immediate answer of 60.8 million; however this is just the UK population rather than the number of mobile phone owners.

Andrew Yates, chief executive of market surveillance firm Artesian Solutions, argued that next generation web technologies are making the web more useful for businesses.

"Developments like Wolfram Alpha will ultimately mean business people can avoid ‘fumbling in the dark’ for the information they need," he added.