5 guides on analytics for newsletter and email marketing creators.
Two sponsored slots at a $30 CPM with a 40% open rate earn about $1.25 per subscriber per year. Against a defensible CAC near $2 and cost-per-signup commonly $2-5, most paid acquisition is at or past break-even before you account for paid cohorts converting worse than organic ones.
Long-tenured subscribers convert three to five times better than new ones, and later cohorts are acquired more broadly than early ones. Both effects correlate with join date, so they cancel inside your blended conversion rate — and the two situations they describe call for completely opposite responses. The same-tenure comparison that separates them.
Every article about Apple Mail Privacy Protection says open rates are unreliable. None of them explain the part that actually changes your decisions: MPP doesn't add random noise, it systematically compresses the measured gap between two subject lines by roughly 3x — which is why so many creators ran good tests, saw flat results, and concluded subject lines don't matter.
Your list has a maximum size you can calculate today: monthly new subscribers divided by monthly churn rate. At 500 signups a month and 2% churn, you will approach 25,000 and stop — no matter how long you keep publishing. The math behind the plateau, why halving churn beats doubling acquisition, and the one term that removes the ceiling entirely.
A 60% open rate sounds great until you realize it's from 800 people and you're earning $0.08/subscriber. The metrics that actually predict newsletter success — revenue per subscriber, engagement score, churn rate, CPM efficiency, subscriber LTV — and what good looks like at every stage.