Deliverability
Feedback Loop (FBL)
A service where ISPs notify senders when recipients mark their emails as spam.
Definition
A Feedback Loop (FBL) is a service provided by mailbox providers that notifies senders when recipients mark their emails as spam. When a complaint is filed, the FBL sends a report to the sender containing the original email (with the complaining address often redacted). This allows senders to remove complainers from their lists and identify content or targeting issues.
Pro Tip
Register for FBLs with major providers (Yahoo, Microsoft, etc.) and immediately suppress addresses that complain.