What is reputation-based spam filtering?

Reputation-based spam filtering makes decisions based on the sender's track record rather than the content of any individual message. It asks: has this sender been trustworthy in the past?

Reputation signals include IP address history, domain age and behavior, complaint rates, bounce rates, spamtrap hits, and engagement metrics. Providers maintain internal databases tracking these signals over time.

A sender with strong reputation gets the benefit of the doubt. Their messages are more likely to reach the inbox even if the content looks promotional. A sender with poor reputation faces extra scrutiny on every message.

Reputation-based filtering is efficient because it leverages accumulated knowledge. Rather than analyzing every message in isolation, it uses history to inform predictions.

Reputation filtering is the harbor keeping records of every ship that has ever visited. Trusted traders sail in smoothly. Unknown vessels face inspection.