This is Part 4 — the final installment of our Media Growth Intelligence series. Everything we’ve measured leads here: how fast and how efficiently your growth engine runs.
Parts 1-3 covered which audience to acquire, how to activate them, and how to retain them. Those metrics answer “what’s working.” These two answer “how well is it working?” — the speed at which audience members move through your monetization funnel and the margin efficiency of every dollar you invest in growth.
If the previous metrics are your growth engine’s instruments, these are the speedometer and fuel gauge.
Quick glossary: Monetization velocity = the speed at which audience members reach key value milestones (first engagement, paid conversion, referral). Growth Efficiency Score = revenue generated per dollar of growth investment. Revenue composition = the split between recurring/predictable revenue and transactional/one-time revenue — a health indicator for sustainability.
Metric 9: Monetization Velocity
What it measures: The speed at which acquired audience members reach revenue milestones, tracked through three time-to-value metrics adapted to each media model.
T2E — Time to Engagement: Median days from signup to sustained engagement behavior. The first velocity checkpoint.
For newsletter publishers: Signup to first open is typically same-day. The real milestone is sustained engagement: 3+ opens of first 5 sends. Morning Brew grew from 100K to 1.5M subscribers in 18 months — their referral flywheel depended on velocity from signup to engaged to referring. beehiiv’s median: 66 days from first subscriber to first dollar of revenue for new newsletters.
For ad-supported media: First visit to email capture, then registration to 5th visit (the habit threshold). Each milestone has a time window: email capture within 2 visits, 5th visit within 30 days of registration. If 5th-visit timing stretches beyond 30 days, the habit isn’t forming.
For paid subscription: Trial to paid conversion is the primary velocity metric. Target: 20-40% trial-to-paid within the trial window. Monthly to annual conversion should happen within the first 3 billing cycles — after that, the monthly habit is set and conversion rates drop.
For membership businesses: Community-led acquisition closes 72% within 90 days versus 42% for sales-led (2x velocity). The example path: free event (Day 0) → forum engagement (Day 14) → $9.95 bootcamp (Day 30) → peer referral (Day 45) → $15K membership conversion (Day 65).
T2P — Time to Paid: Median days from first contact to first paid transaction.
- Newsletter: Free to paid tier: 30-60 days is strong. Beyond 90 days, conversion probability drops sharply.
- Ad-supported: Anonymous to paid subscriber: metered access models show 60-120 day windows for regular readers.
- Paid subscription: Trial to active paid: within trial period (typically 7-30 days).
- Membership: Application to dues payment. High-ticket ($15K+) closes in 30-90 days with community-sourced leads.
T2R — Time to Referral: Median days from activation to first referral action. The flywheel metric.
- Newsletter: Subscriber to first referral share. SparkLoop and beehiiv referral programs show 14-45 day windows for active referrers.
- Membership: Member to first colleague introduction. 20-30% of new members make a referral within 90 days in healthy communities.
The flywheel formula: (Referral-sourced audience / Total active audience) x (1 / Avg days from referral to activation). Higher ratio and shorter cycle = faster compounding.
What velocity tells you that conversion rate doesn’t: A 5% free-to-paid conversion rate looks the same whether it happens in 30 days or 180 days. But 30-day velocity means faster cash return, shorter CAC payback, and more compounding cycles per year. Velocity is the multiplier on top of conversion.
Where the data lives
Velocity metrics come from timestamped events across platforms. Email platform (beehiiv, ConvertKit, ActiveCampaign) provides signup dates, first open, engagement milestones. Payment platform (Stripe, Memberful) provides first payment, plan changes, upgrade dates. Community platform (Circle, Discourse) provides event attendance, referral actions, peer introductions.
The challenge is connecting the journey across platforms. A member who attended a free event, joined the forum, enrolled in a bootcamp, and converted to full membership has four timestamps across three platforms. A warehouse (BigQuery + dbt) joins these into a single velocity measurement per audience member. This is Phase 2-3 work in the implementation roadmap.
Metric 10: Growth Efficiency Score
What it measures: How much revenue your growth investment produces — and whether that revenue is sustainable. The efficiency metric that ties everything else together.
The formula:
Growth Efficiency Score = Revenue from Growth Activities / Total Growth Investment
For newsletter publishers: Subscriber revenue (paid subscriptions + sponsorship ARPU) divided by growth investment (paid acquisition + referral program costs + content production). Paid subscriber LTV runs $100-$300 for B2B newsletters. Acquisition cost: $20-$80 per paid subscriber. Healthy LTV:CAC above 5:1 for paid channels, above 10:1 for organic.
For ad-supported media: Incremental ad revenue divided by content + distribution investment. SEO-sourced readers produce the highest efficiency (long-tail content generates revenue for years at near-zero marginal cost — $30-$100/yr value per ranking article). Social-sourced readers produce the lowest ($1-$5 CPM, one-time engagement). The efficiency gap between channels can be 10-20x.
For paid subscription: New ARR divided by acquisition + retention investment. The NYT example: $300-$500 CAC, $39/yr starter ARPU, 18-30 month payback. But at 70% year-2 retention for annual subscribers, the long-term LTV justifies the front-loaded investment.
For membership businesses: $15K/yr dues at 90% retention = $150K lifetime value per member. Even at $5K CAC (high-ticket sales-assisted), that’s 30:1 LTV:CAC. The efficiency of membership models is structurally high — the challenge is maintaining retention, not improving acquisition efficiency.
Revenue composition — the sustainability indicator:
Not all revenue is created equal. The split between recurring and transactional revenue determines how fragile your growth efficiency is:
- Recurring/predictable: Subscriptions, memberships, annual contracts, recurring sponsorships. This revenue persists without re-acquisition.
- Transactional/one-time: Single event tickets, programmatic ad revenue, one-off sponsorships. This revenue must be re-earned every period.
Target: 50%+ recurring. Below 30% recurring means your revenue base resets every quarter — growth efficiency is illusory because you’re perpetually re-acquiring revenue.
Blended efficiency targets:
- LTV:CAC above 5:1 for paid channels, above 10:1 for organic
- Organic growth ratio trending toward 60%+ of total audience growth
- Moving 10% of audience from Consumer tier to Contributor tier generates more revenue than acquiring an equivalent number of new audience members
Where the data lives
Growth efficiency requires joining revenue data (Stripe, ad platforms) with cost data (ad spend, content costs, platform fees, staff allocation). MER (revenue / ad spend) is a spreadsheet metric you can calculate today. Full growth efficiency requires a warehouse.
A dbt model that joins revenue per subscriber with acquisition cost by channel and retention data gives you true efficiency by segment. The organic ratio comes from UTM-tagged acquisition data in GA4. Revenue composition comes from payment platform categorization (recurring vs. one-time). This is Phase 4 — the capstone metric.
Engagement Scoring Architecture
These 10 metrics work best when they feed a unified engagement scoring system. The weights vary by model:
Newsletter weights: Email engagement (40%), Content depth (25%), Referral activity (15%), Commercial signals (10%), Social sharing (10%).
Ad-supported weights: Content depth (35%), Visit frequency (25%), Newsletter engagement (20%), Registration/account (10%), Social engagement (10%).
Membership weights: Event participation (30%), Community contribution (25%), Content engagement (20%), Communication responsiveness (15%), Commercial signals (10%).
Five engagement tiers: Champion → Contributor → Participant → Consumer → Passive.
The critical insight: moving 10% of your Consumer tier to Contributor generates more revenue than acquiring an equivalent number of new audience members. Engagement scoring tells you exactly who to target and what signals predict upward movement.
Implementation Roadmap
These 10 metrics don’t all require a data warehouse on Day 1. Here’s the build sequence:
Phase 1 (Weeks 1-4) — Blended Baselines: Email engagement metrics from your platform (open rates, CTR, subscriber growth). Blended acquisition cost from ad dashboards. Revenue per subscriber baseline. Churn/unsubscribe rate. Cost: existing tools only.
Phase 2 (Weeks 5-10) — Retention Infrastructure: Automated re-engagement flows triggered by engagement decline. Basic decay scoring (email engagement + visit frequency). Velocity metrics from payment timestamps. Referral program setup (SparkLoop, beehiiv, or custom). Cost: existing platforms + setup time.
Phase 3 (Weeks 11-16) — Segmented Analytics: Cohort analysis by acquisition channel. CAC payback by segment. Expansion signal scoring across platforms. Engagement tier assignment. Requires: BigQuery + dbt initial build. Cost: warehouse setup + modeling.
Phase 4 (Weeks 17-24) — Full Framework: BigQuery warehouse with automated ingestion from email, payment, analytics, and community platforms. dbt models for all 10 metrics. Automated dashboard (Looker/Hex). Reverse ETL to email platform for score-based segmentation and flow triggers. Full growth efficiency calculation with revenue composition. Cost: warehouse + BI tool + reverse ETL.
Each phase delivers standalone value. You don’t need Phase 4 to benefit from Phase 1. But the compounding effect of the full stack — where every metric informs every other — is where the framework generates returns that individual metrics can’t.
What These Two Metrics Give You
Monetization velocity tells you how fast your growth engine converts audience into revenue. Growth efficiency tells you how much return each dollar of investment produces. Together, they answer the question every media operator needs to answer: is this growth engine getting better or worse?
Rising velocity with stable efficiency means the flywheel is accelerating. Stable velocity with declining efficiency means you’re spending more to maintain the same pace. The combination reveals what neither metric shows alone.
This completes the Media Growth Intelligence series. These are the 10 metrics we build during every media engagement — from blended baselines you can measure this week to the full warehouse-powered framework that compounds over quarters. Book a Sprint to see which ones your data can already support.
The full series:
- Part 1: Acquisition Economics — multi-stream audience value and CAC payback
- Part 2: Activation Economics — audience activation, AQL scoring, touchpoint attribution
- Part 3: Expansion & Retention — expansion signals and engagement decay
- Part 4: Efficiency Metrics — monetization velocity and growth efficiency (you are here)
