Pay-Per-Email Plan to Beat Spam and Help Charity

Aug. 13, 2009— -- Yahoo! wants to reinvent the postage stamp to cut spam. Researchers are testing a scheme where users pay a cent to charity for each email they send – so clearing their inbox and conscience simultaneously.

You may see less spam these days, but it is more abundant than ever, making up more than 90 per cent of all email sent globally. Most is intercepted by anti-spam programs that filter mail by its origin or content.

Yahoo! Research's CentMail resurrects an old idea: that levying a charge on every email sent would instantly make spamming uneconomic. But because the cent paid for an accredited "stamp" to appear on each email goes to charity, CentMail's inventors think it will be more successful than previous approaches to make email cost. They think the cost to users is offset by the good feeling of giving to charity.

Pay Per Post

Some previous schemes, such as Goodmail, simply pocketed the charge for the virtual stamps. Another deterred spammers by forcing computers to do extra work per email; and Microsoft's version requires senders to decipher distorted text.

The problem with any such "economic" approach is that it costs money or effort for legitimate senders as well as spammers, Yahoo! researcher Sharad Goel explains. By passing the money onto a charity of the sender's choice, and showing the donation in a "stamp" at the bottom of every email sent, CentMail aims to make senders feel an altruistic glow to balance that perceived cost. That could also persuade people to sign up without waiting for the system to become widespread. "We think this is a more socially efficient approach to reducing spam," says Goel.

Critical Mass

Once the scheme grows more popular, mail-server operators can save resources by having their systems spend less time scrutinising CentMail-accredited messages as spam suspects, its designers say.

CentMail draws inspiration from an IBM project called Charity Seals, created by Mark Wegman and Scott Fahlman. It was never implemented, though, in part because people are not used to paying for email, says Fahlman, currently at Carnegie Mellon University in Pittsburgh, Pennsylvania.

"Some people think that if you put any kind of barrier in the way of sending email, it's sacrilege," says Fahlman. But with the charity-centred approach that barrier is reduced, he says.

Charitable Disagreement

Barry Leiba, also at IBM, points out that one of CentMail's core features could also be a weakness, though.

People may not wish to receive messages plugging a cause they don't agree with. "I might feel that by accepting his messages, I'm implicitly supporting his charity choices – choices that I might be vehemently against."

CentMail is currently in private beta, but Goel hopes that it will soon be released publicly and will be usable with any email address – not just Yahoo! accounts. Users will buy stamps in blocks in advance. You can sign up on the CentMail website to be told when the service goes live.