Feedback Loop (FBL)

What is it?

What is it?

A "Feedback Loop (FBL)" is a mechanism provided by email service providers (ESPs) and internet service providers (ISPs) that enables email senders to receive notifications or feedback about the engagement and behavior of recipients regarding their email messages. FBLs help senders monitor subscriber complaints, identify potential issues with email campaigns, and maintain a positive sender reputation by promptly addressing subscriber concerns.

Key points to remember

Key points to remember

  • Complaint Notification: FBLs notify email senders when recipients mark their messages as spam or junk, allowing senders to identify and address potential issues such as unsolicited emails, irrelevant content, or frequency concerns.

  • Sender Reputation Management: Monitoring FBL reports helps senders identify patterns of subscriber complaints, minimize negative feedback, and maintain a positive sender reputation with ISPs and mailbox providers, which ensures email deliverability.


  • Actionable Insights: FBL data provides valuable insights into subscriber preferences, engagement levels, and satisfaction with email content, allowing senders to optimize their email campaigns, improve targeting, and enhance the overall subscriber experience.


  • Integration: ESPs often provide tools and interfaces for managing FBL subscriptions, accessing complaint data, and taking appropriate actions, such as suppressing complainants from future mailings or investigating the root causes of complaints.


  • Regulatory Compliance: Compliance with industry regulations such as CAN-SPAM (Controlling the Assault of Non-Solicited Pornography And Marketing) requires email senders to honor unsubscribe requests and promptly address recipient complaints received through FBLs to avoid penalties and maintain legal compliance.

Example of Use

Example of Use

  1. Complaint Resolution: An email marketer receives FBL notifications indicating that several subscribers have marked their promotional emails as spam. The marketer investigates the complaints, identifies the underlying issue (e.g., irrelevant content), and takes corrective actions to improve future campaigns.


  2. Subscriber Engagement: A company uses FBL data to analyze subscriber engagement trends and preferences, tailoring email content, frequency, and targeting strategies to better align with subscriber interests and reduce complaint rates.

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