Spiff!
Yahoo is introducing "DomainKeys". It's an open source attempt to stem the flow of spam by having source domains sign outbound email using a private key. It will cut down on the number of spoofed domains available to spammers. Granted, it will require folks adopting it, checking it, and keeping several thousand public keys around, but it's not a bad approach.
Of course, sitting here thinking about it i wonder what ISPs will think of it.
