Interesting Spam-Stopping Idea--The Digital Penny Black Stamp

In 1840, the British General Post Office transferred the cost of mail delivery from the recipient to the sender by introducing the pre-paid postage stamp called the Penny Black. We all know that spam (or unsolicited commercial email) exists because it costs virtually nothing to send out billions of spam messages. It costs the recipient a lot as measured by the time having to deal with it and occasionally as money lost because of a lost opportunity or a crossed-up client due to an error made in dealing with all the spam. This New York Times article describes a way of instituting a cost to send email that would only affect very large volumes of email--the cost, rather ironically, is in time to the sender. The Penny Black Project has developed a way to "stamp" email that has gone through a time consuming process, say 10 seconds, before it is sent. The recipient server simply determines if the "stamp" exists and discards the email if not. Now, a 10 second or so delay would be nothing to sending normal email but it would make spam as it is done today completely uneconomical. Sounds like a good idea to us. The Penny Black Project's developer now works for Microsoft which is the only thing that gives us cause for pause.... [Dana Baggett]