Here are some statistics that illustrate the scale of what we’re seeing:
76.9% of the emails we received are signed according to the (DKIM) standard. Over half a million domains (weekly active) have adopted this standard. 89.1% of incoming email we receive comes from SMTP servers that are authenticated using the SPF standard. Over 3.5 million domains (weekly active) have adopted the SPF standard. 74.7% of incoming email we receive is protected by both the DKIM and SPF standards. Over 80,000 domains have deployed domain-wide policies that allow us to reject hundreds of millions of unauthenticated emails every week via the DMARC standard.
Msg#: 4628608 posted 4:16 am on Dec 9, 2013 (gmt 0)
DKIM is very tough to implement compared to SPF. That huge 74% portion of the pie where both SPF and DKIM are implemented I'm going to assume is primarily people using Gmail/Hotmail/Yahoo mail and the like.
DMARC is something I use on my domains, but I only set it to report, not reject mails. I'm a bit surprised there are 80K domains using DMARC that way.