Goodmail is an accreditation service, in other words a service that vouches for the sender of the message, certifying that they are who they say they are and that their practices conform to a set of standards for good behavior.
Encrypted tokens are included with the message, and custom software in the mail client confirms the validity of the tokens and the message, thus confirming that the messages are valid CertifiedEmail.
Goodmail is not the first accreditation service; BondedSender has been around for years; it works on a bond principle rather than on per-message fees, and lacks the visual cue for the recipient that Goodmail has.
Misinformation abounds: Recipients of "CertifiedEmail," the messages in question, pay nothing for receiving them. The cost is borne by the sender.
Users who wish to send mail to systems, such as AOL, that support Goodmail dont have to use Goodmail to send it.
Such mail will go through conventional filtering software, user blacklists; there is a chance that it will get blocked for the wrong reasons (for example, it will generate a false positive), but that was true in the pre-Goodmail days, so nothing has been lost.
Heres another important point: CertifiedEmail is not supposed to diminish the amount of spam. Saying that it wont is like saying it wont solve global warming; its not supposed to.
What its supposed to do is to get a senders mail through to the user without impediments from anti-spam infrastructure and with an enhanced degree of confidence for the recipient. Its an anti-spam solution for senders, not for recipients.
The confidence thing is not just Goodmail marketing-speak. As a user, I would view CertifiedEmail in a different light than other mail. I absolutely would trust it more, not that I would necessarily want to receive it.
If I got a certified e-mail from a vendor I didnt want to deal with, I would feel OK about clicking the unsubscribe link.
In fact, Goodmail is planning a CertifiedUnsubscribe feature whereby they would act as an intermediary for recipients to remove them from lists. Whats not to like?