# Feedback loop (FBL)

Source: https://joinbreaker.ai/newsletter-glossary/feedback-loop

A system where ISPs tell senders when users mark emails as spam. It helps identify and remove unhappy subscribers.

It's important to note that Google does not provide a feedback loop to ESPs. So monitoring your spam complaint rate in [Google Postmaster](https://gmail.com/postmaster/) and suppressing subscribers who have stopped engaging with your emails is crucial.