A number of top ISPs are putting in place, or have already established, domain-based reputation systems. It is a major shift in how email messages are delivered - one for which email marketers clearly need to prepare.

The good news is that if they have already been keeping their lists clean and focusing on subscriber engagement, the change should not be a dramatic one.

Moving Steadily

There is little doubt that ISPs are steadily moving in this direction, according to a recent report [pdf] by Pivotal Veracity, based on conversations with several ISPs. It has found that AOL, Yahoo, Windows Live, Comcast, Verizon, Road Runner, Bell Canada and CloudMark are all augmenting IP‐based reputation systems with portable domain‐based reputation systems for those mailers using DomainKeys/DKIM authentication.

"This means, ISPs will 'attach' (compute) your spam complaint rates, unknown user rates, and spam trap rates to your domain (this will be the domain you are authenticating which for most mailers will be the 'friendly from' domain) in addition to your IP," Pivotal Veracity said. For better or worse, emailers take their reputations with them, no matter which service provider or vendor they use.

Still the Same in Some Ways

This shift, however, should not be a traumatic one for marketers: ISPs will continue to use much of the same tools they always have such as IP and URL reputation, content filtering and subscriber engagement. Marketers that have been taking these factors into account shouldn’t have that much difficulty transitioning to a domain-based reputation system.

Tips to ease the transition include:

Watch what Google does and plan accordingly. Google has already implemented an authenticated domain reputation system using both DKIM and SPF (sender policy framework) together, according to ReturnPath.

Some of the metrics that Gmail looks at - and ones that Yahoo, AOL, and anyone else creating a domain reputation system are also likely to employ - are:

• How many times mail from this domain went into the spam folder automatically, due to IP reputation or content filters.

• How many times mail from this domain went into the inbox automatically.

• How many times a user marked a message from this domain as spam.

• How many times a user marked a message from this domain as "not spam."

• What should senders do now take advantage of domain reputation when it becomes more widely adopted?

Focus on authentication and certification. Domain reputation will be based on authentication, ReturnPath also says. "Specifically at AOL, Yahoo!, and some of our other ISP partners (who haven't announced their systems yet) it will be based on DKIM."

At Yahoo!, the Return Path Certification Program trumps both IP and domain reputation, ReturnPath also reports. "We certify that you are good sender - as long as you maintain the reputation standards set by the program you don't have to worry about changes to the way Yahoo! handles email."

It's all about portability. This can work to email marketers' unexpected advantage, according to Deliverability.com. Marketers with a high score will be able to leverage it and essentially have ESPs clamoring for their business "much like a client with a good credit score who intends to find the best interest rate possible on a mortgage."

Watch for new tools. A few months ago Pivotal Veracity released a new tool, MailboxIQ, to track many of the same metrics used in domain based reputation systems. Expect more to come to market as ISPs make their systems' requirements clear.