Articles in this category WHAT Are FEEDBACK LOOPS aka COMPLAINT LOOPS (FBLs)? Summary Feed-Back-Loops (FBL) are a way for large ISPs to let you know that someone has made a complaint to THEM about a message we have sent them on your behalf. This is not a bounce, or re... SETTING UP FEEDBACK AKA COMPLAINT "LOOPS" (FBLs) Overview If you are going to send bulk email you need to know something about feedback-loops or complaint loops. What Are FBL/Complaint Loops? Feedback (FBL) or Complaint "Loops" are mechanisms where ...