I believe that our public statements make it clear that we realize that significant use cases are broken: http://yahoo.tumblr.com/post/82426971544/an-update-on-our-dmarc-policy-to-p rotect-our-users http://yahoomail.tumblr.com/post/82426900353/yahoo-dmarc-policy-change-what -should-senders-do Elizabeth Zwicky