DomainKeys Identified Mail (DKIM), a synthesis of email authentication work by Yahoo, Cisco, and other companies, holds a key advantage for email marketers beyond getting mail to recipients.

From time to time, news emerges on a company finding its usual email messages being treated as villainous rapscallions, denied entry to inboxes where they once arrived without incident. One day email’s traveling without incident, the next day it turns into O’Hare Airport on a snowy holiday weekend.

One’s email campaign doesn’t need to suffer from an unnecessary blockage (we mean this for legitimate opt-in marketers; you spammers deserve intestinal blockages along with your email being stuffed). We give credit to Mark Risher, group product manager for Yahoo Mail, for letting us know in an interview a mildly hidden benefit of DKIM.

Briefly, DKIM lets a mail server know an incoming message from a domain actually came from that domain. DKIM-capable mail servers check this and pass approved messages through.

Risher noted how in our piece about Google’s Gmail using DKIM to stop PayPal and eBay phishes, Google is knocking out a lot of incoming junk. As in more than a billion such messages per day.

Here’s why DKIM matters to legitimate email marketers. The technology authenticates a message as legitimately coming from the domain that sends it. The IP address for the domain may change; it’s not important to DKIM for authenticating email.

We think that’s a big selling point for anyone doing email marketing, one that hasn’t been emphasized enough. Instead of losing precious time reaching customers while making a change of hosting services and the relevant IP addresses, DKIM keeps the authentication in place and recipient servers happy.

Adoption continues apace throughout the Internet space, and Risher also said banking industry consortium BITS recommended adoption of DKIM for financial institutions. That would go a long way toward restoring trust in email messages from banks, a regularly spoofed item by criminal phishers.

Yahoo maintains a resource at postmaster.yahoo.com about contacting its domain with email. DKIM will help email marketers do so.