Definition
Marginal revenue per send measures whether each additional email you send is economically worthwhile. The first email of the week might generate significant revenue. The seventh email might generate almost nothing while still costing send volume and risking unsubscribes.
How It Works
Track revenue by send position within a week or month. Plot send count against total revenue. The point where the curve flattens is your marginal revenue ceiling. Sending beyond it adds cost without meaningful return.
Why It Matters
Most senders optimise for per-campaign ROI while ignoring the declining marginal returns of high frequency. Marginal revenue analysis helps you find the frequency sweet spot that maximises total revenue without wasting send volume or burning subscriber goodwill.
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.
Announcement Email
An announcement email is a dedicated campaign that communicates a specific update, milestone, or change to subscribers, from product launches and feature releases to company news and events.
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.
B2B Email Marketing
B2B email marketing targets business professionals and organisations with longer sales cycles, educational content, and relationship-driven campaigns compared to B2C email.
B2C Email Marketing
B2C email marketing focuses on sending targeted promotional and transactional emails to individual consumers, emphasising personalisation, urgency, and direct response.