Microsoft: The Next Step to Deterring Spam
Interesting technical spefications on batteling emails spamming, what say you ?
Caller ID for E-Mail Technical Specification
Two documents for you to read:
1) "Caller ID for E-Mail: The Next Step to Deterring Spam"
2) "Protecting Domain Names from Spoofing: A Guide for E-Mail Senders"
and implementation license doc:
"Caller ID for E-Mail Implementation License"
You can also get the techonlogy and policy proposal located here.