Definition
A spam score evaluates your email against hundreds of rules used by major ISPs. A score of 0 is clean. Scores above 3 indicate a high probability of spam folder placement. Testing tools check content for trigger words, HTML code quality, link reputation, authentication setup, and sending infrastructure. Most ESPs include basic spam scoring in pre-send workflows. Dedicated tools like Mail-Tester and Litmus provide detailed breakdowns.
Common Thresholds
- 0-1: Clean — safe to send
- 1-2: Moderate risk — review flagged items
- 2-3: High risk — significant changes needed
- 3+: Very high risk — do not send without complete rewrite
Related Glossary Terms
A/B Testing
A/B testing in email marketing is the practice of sending two variations of an email to a small sample of your list to determine which version performs better before sending the winner to the remaining subscribers.
AOL Mail for Email Marketers
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ARPU (Average Revenue Per User)
ARPU (Average Revenue Per User) is a metric that measures the average revenue generated per email subscriber over a specific period, used to evaluate list value and campaign effectiveness.
Attention Rate
Attention rate is the percentage of email opens that last longer than 5 seconds, distinguishing genuine reads from passive opens, preview-pane views, or Apple MPP auto-loads.
BIMI
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Bounce Rate Threshold
A bounce rate threshold is the percentage of hard or soft bounces at which email platforms and ISPs begin to penalise sender reputation, typically around 2-5%.