On Mon, Apr 14, 2014 at 11:24 AM, Jim Popovitch <jimpop@gmail.com> wrote:
DMARC hasn't cut down on yahoo spam so far. Yahoo's spam problem was (is?) centered on account hijacks.
I just checked my spam folder for the past month. Out of about 80 messages "from" Yahoo, I can see about 3 that went via Yahoo's mail servers. ie, >90% were/would have been blocked using DMARC. Of course, I'm sure the spammers will simply start changing yahoo.com to somethingelse.com once they realize - but from Yahoo's perspective, that's obviously a positive. Whilst I don't agree with the way that Yahoo has done this (particularly around communication), I think the end result is only going to be positive. At a high level it's no different than when people started rejecting mail from hosts without PTR records, or when ISPs started blocking outbound port 25 - they both caused things to break, and both caused people to have to take action to fix the brokenness, but in the long run they were both hugely positive. Scott