That's why we get so much junk e-mail: It's essentially free to send. So Microsoft Corp. chairman, Bill Gates, among others, is now suggesting that we start buying "stamps" for e-mail.
Many Internet analysts worry, though, that turning e-mail into an economic commodity would undermine its value in democratizing communication. But let's start with the maths: At perhaps a penny or less per item, e-mail postage wouldn't significantly dent the pocketbooks of people who send only a few messages a day. Not so for spammers who mail millions at a time.
Consider how simple and inexpensive it is today to e-mail a friend, relative, or even your local MP. It's nice not to have to calculate whether greeting grandma is worth a cent. And what of the communities now tied together through e-mail -- hundreds of cancer survivors sharing tips on coping; dozens of parents coordinating soccer schedules? Those pennies add up.
Though postage proposals have been in limited discussion for years -- a team at Microsoft Research has been at it since 2001 -- Gates gave the idea a lift in January at the World Economic Forum in Davos, Switzerland, as part of Microsoft's anti-spam strategy. Instead of paying a penny, the sender would "buy" postage by devoting maybe 10 seconds of computing time to solving a math puzzle. The exercise would merely serve as proof of the sender's good faith. Time is money, and spammers would presumably have to buy many more machines to solve enough puzzles.
Critics of pay-for-email see more promise in other approaches, including technology to better verify e-mail senders and lawsuits to drive the big spammers out of business.
"Back in the early '90s, there were e-mail systems that charged you 10 cents a message," said John Levine, an anti-spam advocate. "And they are all dead."