A plan from Yahoo and AOL to adopt an email certification system that charges mass mailers a per-message fee is stirring concern in the market.

It has been more than three months since Yahoo and AOL announced their intention to adopt technology from Goodmail to further reduce the amount of spam and fraudulent phishing email in their users' inboxes. That announcement last October raised few eyebrows, but as Yahoo and AOL get closer to implementation, critics are speaking up.

Tom Gillis, senior vice-president of worldwide marketing at IronPort, a provider of email security products to large corporations and ISPs, has voiced widespread concerns.

Charging mass mailers a fee is ineffective, because spammers are awash with cash, Gillis contends. Rather, systems should use other methods to authenticate senders' identities and evaluate their reputations.

Technologically, Goodmail's proprietary architecture is "very invasive", Gillis claimed. "It needs to be carefully implemented," he said, "because it goes right into the mail flow. We'd worry about scalability and reliability."

Consequently, IronPort, whose clients include Dell, Gap, Nasdaq, Time Warner's RoadRunner and eBay's PayPal, remains disinclined to adopt Goodmail's technology. Instead, IronPort supports open-standards approaches that eschew sender fees, such as DomainKeys, backed by Yahoo and others, and Sender ID, whose backers include Microsoft, he said.

But Richard Gingras, Goodmail's chairman and CEO, said existing approaches to combat spam and phishing fall short, claiming that consumers today are unwilling to open, let alone reply to, email messages from commercial entities.

This has created a major disconnection in email communications between legitimate organisations and their clients. "The inbox isn't safe and consumers don't trust commercial messages," he said.

He questions naysayers' motivation. "The criticism is coming from those who serve email marketers and who would rather the system continue the way it is, as unfortunate as that might be," Gingras said.

Goodmail's CertifiedEmail service isn't at all about making consumers pay for sending email; it charges commercial bulk senders. Goodmail rigorously evaluates senders before accepting them into the scheme, and subsequently monitors them continuously to ensure they send solicited, legitimate email, Gingras said.

The fee of between a quarter of a cent and one cent per message serves as a further incentive for senders to be conservative in their mail volume, he added.

Goodmail grants its senders encrypted tokens to embed in their messages, which in turn arrive with an icon in inboxes denoting certified legitimacy. The American Red Cross and The New York Times are testing the system.

AOL email users will begin to see Goodmail certification icons within the next 30 to 60 days, said AOL spokesman Nicholas Graham. Goodmail's program is optional for commercial senders; AOL will keep using its existing email scrubbing filters, which don't apply a fee to senders, he said.

Meanwhile, Yahoo is "planning to test" the Goodmail system in coming months to provide added protection to users, the company said in a statement.