How do feedback loops influence IP reputation?

Feedback loops (FBLs) are reporting mechanisms where mailbox providers notify senders when recipients mark messages as spam. They directly influence IP reputation in two ways:

The complaint itself hurts reputation: When a recipient clicks "Report Spam," that signal goes into the provider's reputation calculation for your IP. High complaint rates trigger filtering or blocking. The threshold is low: 0.1% is concerning, 0.3% is dangerous.

FBL data enables remediation: Receiving complaint notifications lets you suppress those addresses immediately, preventing future complaints from the same recipients. Without FBLs, you'd keep emailing people who complained, compounding the damage.

Major FBL programs:

Yahoo/AOL: Standard FBL via email notifications

Microsoft: JMRP (Junk Mail Reporting Program) via SNDS

Gmail: No traditional FBL, but spam rate appears in Postmaster Tools

To use FBLs effectively:

Register for all available programs

Set up automated processing to suppress complainers instantly

Monitor complaint sources to identify problematic campaigns

Track complaint rates as a key deliverability metric

FBLs are your early warning system. They tell you when recipients are unhappy before that unhappiness escalates to blocks.