Feedback loops (FBLs) - often called complaint feedback loops. This is complaint data collected by Mailbox Providers which provided to anyone that has signed up for these FBLs.
This data is collected directly from the recipients who click on the ‘report as spam’ button within the Mailbox. This complaint message then gets returned to the originating sender (or ESP/Bulk mail provider) through a designated email address that the sender has set up.
A Feedback Loop service is primarily created to give senders the opportunity collect information about potential spammers and prevent further abuse to these recipients that have complained. Usually these recipients are added a Suppression List. Here is a feedback loop list of Mailbox Providers who we have integrated with: