Yahoo introduces DomainKeys
 

DomainKeys: Proving and Protecting Email Sender Identity
Email spoofing - the forging of another person's or company's email address to get users to trust and open a message - is one of the biggest challenges facing both the Internet community and anti-spam technologists today. Without sender authentication, verification, and traceability, email providers can never know for certain if a message is legitimate or forged and will therefore have to continually make educated guesses on behalf of their users on what to deliver, what to block, and what to quarantine, in the pursuit of the best possible user experience.

DomainKeys is a technology proposal that can bring black and white back to this decision process by giving email providers a mechanism for verifying both the domain of each email sender and the integrity of the messages sent (i.e,. that they were not altered during transit). And, once the domain can be verified, it can be compared to the domain used by the sender in the From: field of the message to detect forgeries. If it's a forgery, then it's spam or fraud, and it can be dropped without impact to the user. If it's not a forgery, then the domain is known, and a persistent reputation profile can be established for that sending domain that can be tied into anti-spam policy systems, shared between service providers, and even exposed to the user.

http://antispam.yahoo.com/domainkeys

which btw looks so complicated

This can work, as soon as it is accepted as a standard. They should have done it a while ago.

Its not too complicated either.

It makes it possible to verify that the email came from the sender domain. This way, emails with forged headers will be dropped immediately.

Also it makes it easy to keep track of spam complaints on a per domain basis, and ban the domains that have a high spam ratio.

Spammers won't get around this, or it will be very costly to send spam because you have to keep registering so many domains.

hmm interesting..cant wait to see it in action

I think they WILL keep registering a lot of domains and just figure its a cost of doing business. 6.95 isn't that much to cough up for a domain. :2 cents:

If each domain is blocked just after reaching 100 or even less users, yes it is too much of a cost

It's a good move. If they can make it work things would be more profitable for everyone since people wouldn't be scared to open the inbox. Opt in mail conversions would increase exponentially.