next big thing
There's a scene in David Lodge's 1984 novel Small World when a highly strung academic comes across a computer which has been programmed as a therapist; a kind of sanitised desktop-version of Doctor Ruth. It "listens" to whatever he types in at the keyboard, and responds. It eventually goads him into having a nervous breakdown.
This may sound a bit far-fetched (it certainly did when the novel came out), but the program actually exists and it's called Eliza. It was invented in 1966 by an American computer scientist called Joseph Weizenbaum and you can download versions of it. Eliza was conceived to investigate how humans and computers interact, and to look into something called the Turing test. Named after Alan Turing, an artificial intelligence pioneer, it simply says that a computer is thinking if it can fool a person into believing that it's another person. If you've never come across Eliza or her descendants (try Azile, for example; Eliza's evil twin brother) they are amusing for a few minutes, and some people even find them therapeutic. But you'll quickly see how far short they fall from passing a Turing Test.
Yet Eliza has spawned a number of increasingly sophisticated offspring and imitators over the years, known on the Internet as chatterbots. Often, their creators try to give them characters (even a virtual bartender, for example) and every year there's a competition to see which comes closest to passing a Turing test. Some of the more sophisticated versions run through your web browser and some you can download. But, even 30 years on from Eliza, if you spend any time talking to either type of chatterbot, you'll see programmers remain a long way off from inventing thinking machines. Although they cope well with general questions like "how are you?", as soon as you start asking them specifics (try asking them who Tony Blair is) they quickly reveal their limitations.
You may also come across the occasional chatterbot on IRC systems, networks which let people communicate with each other via their computer keyboard. One of the points about chatrooms is that people can pretend to be anything or anybody they want; a Californian physics professor could, in fact, be a schoolboy in Buenos Aires (or, more likely perhaps, vice versa). Some AI developers have taken advantage of this fact to use chatrooms as places to try out their chatterbots in an attempt to see if they can pass them off as other people.
I even know somebody who has invented an anti-Turing test (although somebody may well have thought of it before; it's not a desperately original idea) where he enters chatrooms and does his best to convince other people that he is, in fact, a computer. So far, he claims, nobody has ever been taken in. But if I was reading this, I'd be worrying about how long it will be before they invent computers that write articles about the Internet.
Then again, perhaps they already have...
Spence's home page. Spence is a virtual bartender who has a penchant for rock 'n' roll.
Software archive which includes versions of Eliza and Azile for both Macs and PCs.
Home for MegaHal, one of the more sophisticated chatterbots.