The DMR Model
Digital ads have never cost more.
Or been worth less.
A cross-channel model of diminishing marginal returns (DMR) on advertising attention, parameterized from primary sources and projected to 2040.
The argument
Every ad you buy is worth less than it used to be.
The price of advertising on every major digital channel has continued to rise. Meta's revenue per US user grew 6.5 times between 2015 and 2023. But the people paying that bill are getting less back per dollar, not more.
Each ad gets less human attention. The audience seeing it has less purchasing power. A larger fraction of impressions go to bots. And ten percent of Meta's 2024 ad revenue came from outright scam ads, per the company's own internal projections leaked to Reuters.
Our model decomposes every impression into four factors — volume, attention, audience quality, legitimacy — and tracks how each one has moved on fourteen channels over a decade. The result: every channel is degrading per-unit, but most are hiding it under volume growth. The exceptions are the channels whose substrate cannot be manufactured.
The four factors
Every impression decomposes into the same four things.
The model treats advertising inventory as a production function. Volume is what platforms sell. The other three are what advertisers actually buy — and they're all degrading.
Impressions
Volume
How many ad slots a channel delivers. The headline number platforms put on their earnings calls. Most channels show massive volume growth — Meta has 7× more impressions in 2025 than 2015. Volume disguises decay.
Attention
Quality per impression
How many seconds of active human attention each ad gets. Anchored to out-of-home (OOH) = 1.00 using Nelson-Field biometric data and Adelaide Attention Units. Premium video gets ~13.5s. Facebook feed gets ~2s. TikTok ~3.5s.
Density
Upper-income reach
What fraction of the audience is in the upper-income tier ($100K+ household income, the top ~33% of US households). Pew documented Facebook's daily upper-income usage falling from 78% in 2015 to 45% in 2025 — the platform inverted from Harvard exclusive to downmarket.
Legit Share
Real ads to real humans
(1 − bot fraud) × (1 − scam ad share). fraud0 measured 21% bot share on paid social. Reuters revealed Meta internal docs projecting ~10% of 2024 ad revenue came from scam ads.
The four archetypes
Channels fall into one of four states.
Substrate cannot be manufactured by adding more impressions. Effective inventory holds or grows in real terms.
Inventory expanding faster than quality degrades. Slope will invert when surface expansion exhausts.
Quality declining across all factors. The mainstream digital advertising DMR story.
Structurally finished or collapsing before maturity. Only niche use cases survive.
Explore
Five views of the same model.
Running to Stand Still
Meta's nominal ARPU grew 6.5x while effective inventory stayed flat.
Channel Ranking
14 channels ranked by quality-adjusted price inflation rate.
Trajectory
Per-impression quality projections, 2015 through 2040.
Decomposition
Which quality factor is dragging each channel down.
Effective CPM Calculator
Your channel mix. Your real cost per thousand impressions of attention.