Best Practices How Do Email Complaint Feedback Loops Work? By Ciara Noonan | 3 minute read Many organizations spend thousands or even tens of thousands sending legitimate marketing emails every day. However, spam is in the eye of the beholder. A percentage of the people on any organization’s mailing lists may think of these marketing emails as spam. It’s in the interest of marketers, email service providers (ESPs), and mailbox providers (MPs) to unsubscribe those users. Mailbox providers — the organizations that handle email delivery to users — and email service providers – for example, MailChimp – are highly sensitive to spam. MPs don’t want their users exposed to spam, and ESPs don’t want to end up on blacklists. Reliable email delivery is important for their business. What is a Feedback Loop (FBL)? Feedback loops are one of the mechanisms by which the email industry attempts to make sure that users don’t receive email they do not want. So how does information about spam reports get from mailbox providers to email service providers? How do they work? FBLs are complex, with many edge cases and exceptions. Here is the ideal scenario: An organization sends marketing emails to its subscribers via an email service provider. Some of the recipients hit the spam button. If the ESP is subscribed to the MP’s feedback loop, the MP sends a standard message to the ESP, letting them know that users have marked mail as spam. The email service provider can pass on the information to the sender so they can remove the user from their mailing lists. The email service provider can also identify accounts that are sending large amounts of email that’s being marked as spam. This may be because of deliberate spamming or because of poorly targeted marketing messages. Why are FBLs important in marketing emails? Marketers can use FBLs to remove bad leads from email lists, avoid their domains getting a reputation for spamming and landing on spam blacklists. They can also ensure mailbox providers don’t send their messages right to the spam folder. Feedback loops help solve some of the problems associated with spam and other unwanted email. But they’re a long way from a comprehensive solution – many mailbox providers don’t offer a feedback loop. Malicious spammers using compromised accounts don’t care about feedback loops; they just want to keep using an account’s resources for as long as possible until it’s blocked. By the time the user hits the ‘spam’ button, however, millions of spam email could already have been delivered. Feedback loops are a useful tool, but they’re a small part of a responsible organization’s anti-spam strategy.