Comment Needs a new innovator (Score 1) 127
As of now PKI for email is just too much work for a normal user, and single emails, or single users, using encryption stand out as people to monitor, anomalous activity.
Someone like Google could add a checkbox in their Labs features that automatically encrypts email between users who have the feature enabled on their system, and publicizes the spec so others can implement on the server side. It doesn't address the authentication side of the equation, but at least could raise the traffic level of encrypted email enough to make purposely encrypted emails noise instead of signal.
Authentication can still be handled by other means, including SSI and self-signed keys.