Gates reveals his 'magic solution' to spam 

The battle to rid the world's in-boxes of spam has got itself a heavyweight champion--Bill Gates--making an even more heavyweight promise: an end to the e-mail plague within two years.

Speaking at the World Economic Forum in Davos, Switzerland, Gates told a group of delegates that he could crack spam by 2006. The soon-to-be-knighted Microsoft chairman added that with the help of some canny tech measures, spammers would be hit where it hurts--in their fat wads of Viagra-inspired cash.

One of the suggestions on Gates' antispam checklist is setting those sending e-mails a simple brainteaser, or asking their PCs to do an easy computation. If you're sending an odd e-mail or two, the time and difficulty wouldn't pose much of a problem. For machines belching out huge amounts of spam day in and day out, however, the cost and computing power needed to send the e-mails off through the ether would be huge.

Microsoft researchers earlier this year demonstrated the technology, which is called No Spam at any (CPU) speed.

Gates also said Redmond, Wash.-based Microsoft is working on another "magic solution" to the spam problem--this time with a focus on the identifying the sender.

The "payment at risk" system would involve e-mail recipients setting a level of payment that would tax the sender, if its e-mail were rejected, low or high, depending on how greatly recipients were bothered by the unwanted e-mail.

The idea goes like this: If you receive an e-mail from an old school friend, and you're happy to receive it, the sender doesn't pay. If it's another offer of a porn subscription, you reject it, and the spammer is forced to cough up.

That's the theory, at least. But Martino Corbelli, a spokesman for U.K. spam-filtering company SurfControl, doesn't buy it. "I think the idea is a nice one, and I don't disagree that in a few years' time, the spam epidemic will reduce--that will happen. But as for charging someone when you don't know who they are and where they are--it's not feasible," he told Silicon.com.

The tech old guard of spam fighting--the humble mail filter--wasn't entirely rejected by Gates. He acknowledged that filters have their part to play in the spam struggle but said he believed that they wouldn't ultimately solve the problem.

Gates' spam offensive has left Corbelli unimpressed. "I think he's right on the timescale; I think he's wrong on the method. We simply don't have the infrastructure to know who to charge," he said.

Jo Best of Silicon.com reported from London.