Three Ways to Rate E-mailers
Internet service providers use three main metrics to gauge a sender’s reputation and determine how to process incoming e-mail.
The formulas are different at each ISP and there are other factors at play, but marketers that are diligent about the following will be well positioned to head off potential delivery problems.
- Spam complaint rate
The percentage of people complaining that a marketer’s e-mail is spam. ISPs use the sender’s spam complaint rate as the No. 1 criterion for determining whether incoming e-mail should be blocked or diverted to the spam folder.
Some experts say this rate should be no higher than 1%. Others recommend striving for 0.25% or lower. All agree that a spam complaint rate over 1% means big delivery troubles for the sender. Claiming the list is 100% opt-in won’t help the marketer, either. If enough recipients say it’s spam, it’s spam.
- Unknown user rate
The percentage of mail going to e-mail addresses that no longer exist. High unknown-user rates mean the mailer has sloppy list hygiene practices. Marketers that try to make the ISPs process their garbage will get punished for it.
- Hitting spam traps
ISPs often turn unused addresses into spam traps. These are addresses that can’t possibly have signed up for anything. How they’re used varies from one inbox provider to another. But if a marketer hits spam traps, the ISP rightfully concludes it’s spamming.
There’s no way to tell for sure which addresses on a list are spam traps, so removing them once they’ve contaminated a list is difficult. In worst-case scenarios, it may be necessary to reconfirm the entire list.
However, spam traps can be avoided by employing strict permission-based address-collection practices and ongoing list maintenance.
