] Instead of implementing a registry that would, at best
] have no impact on spam and, at worst, cause it to
] increase, the FTC%u2019s plan recognizes the need for an
] authentication standard. The FTC%u2019s Report explains
] that %u201Cwithout effective authentication of email, any
] registry is doomed to fail. With authentication, better
] CAN-SPAM Act enforcement and better filtering by ISPs may
] even make a registry unnecessary.%u201D

Apparently, the FTC is holding a summit on mail authentication
in November.