Wolfram|Alpha

What it is

Wolfram|Alpha is a web service that answers a user's question by computing a result from data and algorithms, instead of returning a list of web pages that might contain the answer. The user types a question in ordinary language, and the service tries to work out what is being asked and returns a computed answer. The system was developed and deployed entirely with Mathematica, and by the time of launch it already contained nearly 6 million lines of Mathematica code^[1].

The launch

Stephen Wolfram wrote on 15 May 2009 that Wolfram|Alpha would launch later that day, with the proceedings shown on a live webcast^[1]. The project blog set out the plan in more detail: the first attempt to go live would be on the evening of Friday 15 May 2009, with webcasting of the preparations starting at 7pm CDT^[2]. Wolfram later wrote that he pressed the button at 9:33:50pm central time on 15 May 2009 and Wolfram|Alpha went live^[4]. The team wrote on 18 May 2009 that the service had gone live in test mode at 8:48pm CST on the Friday^[3].

The launch was deliberately staged. The blog said that if all went well, Wolfram|Alpha would be declared officially launched on Monday 18 May 2009^[2], and the team's post of 18 May confirmed that the service was now officially launched^[3]. In other words, the weekend was treated as a live test: the system was open to anyone who came to it, but the formal announcement waited until the team had seen how it held up.

How it works

Wolfram said that at launch the service would run Mathematica on about 10,000 processor cores using gridMathematica-based parallelism, and that every query would be served by webMathematica^[1]. Parallelism here means that a single request can be spread over many processors working at the same time, so that heavy computation does not have to wait on one machine. webMathematica is the part of the stack that takes each incoming query from the web and has it computed^[1].

The most visible feature of the service is its handling of free-form linguistic input: the user does not fill in fixed fields but simply types a question, and the system has to work out what was meant. Wolfram said that this ability relies on symbolic pattern matching in Mathematica^[1]. Pattern matching treats the typed phrase as a symbolic expression and compares it against patterns that describe the kinds of questions the system knows how to answer; when a pattern matches, the corresponding computation is carried out. That approach lets one engine handle many different phrasings of the same underlying question without a separate rule for every sentence.

What happened during the test

By the time the team wrote its 18 May post, the service had processed nearly 23 million queries and had received more than 22,000 feedback messages^[3]. Those two numbers describe different things: the queries show how much traffic the system absorbed while it was still in test mode, and the feedback messages show how much of that traffic turned into comments sent back to the team.

Where it sits

Wolfram|Alpha is an attempt to answer questions by computation rather than by retrieval, and its dependence on Mathematica runs through the whole design: the same symbolic engine that computes results is also what interprets the question^[1]. Its launch in 2009 was unusual in being public and staged at the same time — a webcast of the preparations, a button pressed at a recorded moment, a weekend of live testing, and then an official declaration^[2][3][4].