A new pay-per-message model, currently under consideration by AOL and Yahoo, is meant to avert problems stemming from the flood of spam (junk e-mail) by requiring companies to pay for certified e-mail deliveries, in the same way they pay for certified snail mailings.

There's only one problem: No one seems to believe the system will help to reduce the amount of spam, some critics think it might actually increase junk e-mail, and some are worried that it will set a dangerous precedent by creating two tiers of e-mail service.

What everyone agrees on, however, is that spam is a big problem. According to Postini, a provider of enterprise e-mail management software, over two-thirds (68.6 percent) of all Internet e-mail messages are now spam. And there's currently no good solution to this mushrooming problem. Spam filters are, at best, imperfect, too often failing to keep junk mail out of users' inboxes.

Worse still, such filters occasionally block legitimate mail. Not to mention the effort required to maintain a spam-filtering system, which costs Internet Service Providers (ISPs) time and money.

Enter Goodmail Systems, a provider of e-mail services to ISPs, including AOL. The company's CertifiedEmail system creates a special class of certified messages that qualified -- and paying -- companies can send to their customers. These messages include unique cryptographic tokens, supplied by Goodmail, and they appear with a special "certified" icon in users' inboxes. Both Yahoo and AOL have publicly stated their desire to implement its system -- and AOL says it will do so within 30 days.

AOL insists that it will keep offering its free e-mail service indefinitely, that it will continue to aggressively filter spam, and that it will not demote noncertified messages to second-class status. It also plans to continue its existing Postmaster, Whitelist, and Enhanced Whitelist services, which help legitimate organizations send mail to AOL users at no charge. Furthermore, both AOL and Goodmail claim that they will not permit spammers to send certified messages, and that they'll revoke certification from any company that abuses the system.

Goodmail is not the first company to propose a scheme requiring senders to pay for delivering messages. At the World Economic Forum in Davos, Switzerland in 2004, Microsoft chairman Bill Gates suggested that e-mail "postage" would eventually eliminate spam by reducing the economic incentive for spammers.

But pay-per-e-mail systems have not met with much success -- and every time a new proposal for one has been floated, netizens have reacted with a sound and fury -- as AOL found out last week.

A coalition of more than 50 nonprofits, led by the Electronic Frontier Foundation, has launched a campaign to stop the online giant from implementing its certified e-mail program, which, the nonprofits say, would amount to an "e-mail tax" that could stifle free speech online.