Circle ID has an interesting piece entitled Internet Governance: An Antispam Perspective by Meng Wong, who is known for his work on the email authentication mechanism SPF*:
I believe that we must move to a default-deny model for email to solve
phishing; at the same time we must preserve the openness that made email the
killer app in the first place. The tension between these poles creates a
tremendous opportunity for innovation and social good if we get things right,
and for shattering failure if we get things wrong.
SPF is derived from original concept work by Paul Vixie which is now also the core of Microsoft's Sender ID