Spam Fighters Turn to Identifying Legitimate E-Mail

Spam Fighters Turn to Identifying Legitimate E-Mail: "'Just because we can verify your identity doesn't mean you send good email,' said Miles Libbey, the manager for antispam products at Yahoo. 'You absolutely need identity and you also need reputation.'
Deciding whose mail will be delivered and whose will be bounced is a thankless task, and most proposals envision that several independent groups would publish e-mail standards. A sender would choose one of these to follow, and that group, in turn, would monitor its compliance. "

They say they must go slowly out of respect for the decentralized nature of the Internet (and on the advice of their lawyers).

(Even the Postal Service wants to get into the act, with an electronic postmark.)