Yahoo email anti-spoofing policy breaks mailing lists

[Don]

>> Does anyone know why Don's messages always show up as a message inside a
>> message?
>>
> This seems to be a Yahoo bug of some kind.  Both Don's and Maureen's 
> messages show up with no subject line and, as you noted, like "a message 
> within a message."

http://www.pcworld.com/article/2141120/yahoo-email-antispoofing-policy-breaks-mailing-lists.html

>>
"So users of Gmail, Hotmail and other DMARC-enabled providers will not only 
fail to receive messages sent to the mailing list by Yahoo users, but will 
flood the list with bounce messages, risking to be bounced off the list 
themselves, Levine said.
The email expert recommended that mailing list operators suspend the list 
posting rights of yahoo.com users and ask them to re-subscribe to their 
lists with accounts from different email providers.  (ED:  Yeah, thats a 
great solution?  No one with a Yahoo address can subscribe to a mailing 
list?)

"We are currently experimenting with an anti-abuse technology that helps us 
protect our users from phishing and spoofing attacks," a Yahoo 
representative said via email. "As a result of this experiment, a small 
percentage of our users who use service providers external to Yahoo may 
experience issues. Affected users can visit our help page to learn more. We 
apologize for any inconvenience this may have caused.""

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