Yahoo users can feel a little bit more secure when receiving email from eBay and Paypal after Thursday's Yahoo! yodel: Say goodbye to eBay and PayPal fraudsters.

"We've teamed up with eBay and PayPal to become the first Web mail service to block the delivery of unauthenticated eBay and PayPal emails, reducing your risks of receiving phishing scams or fraudulent emails. Our weapon
is a technology Yahoo! spearheaded called DomainKeys, which uses cryptography to verify the domain of the sender.

This is the first major announcement of this kind, be prepared for more to follow by authenticating your mail now. Not just your commercial or transactional email but also your Corporate email.