Interruption was never free, but for fifteen years the feed made it feel free. A person scrolling a feed had already surrendered the moment; they were between things, idling, open. Sliding an ad into that idle state cost the advertiser a bid and cost the user almost nothing they valued. That bargain, low harm interruption at industrial scale, was the economic engine of social media. It is also over.
The post feed world is not a world without media. It is a world where sessions have intent. People ask questions and get answers. They dispatch agents to compare and buy. They open an app to do a specific thing and leave. The idle scroll, the state that made interruption cheap, is shrinking as a share of digital life, and every year the average moment you interrupt is more likely to be a moment the user actually chose. Interrupting chosen moments is a different product with a different cost curve, and almost nobody has repriced.
I want to do something unfashionable in this paper: take interruption seriously as a tool. I am not going to tell you interruption is dead. Interruption built my industry and it still works when the math works. I am going to show you why the math has changed underneath it.
Key Findings
- The cost of an interruption to the user is proportional to the value of the activity displaced, and post feed activities are systematically higher value than feed scrolling.
- What I call the Displacement Price of an interruption, the user side cost your ad imposes, has been rising invisibly while the advertiser side price has stayed flat, creating a hidden liability on every media plan.
- Interruption in intent driven sessions does not just fail more often; it accrues a compounding Interruption Debt of avoidance behavior: blockers, paid tiers, agent delegation, and platform switching.
- The surviving venues for cheap interruption, remaining feeds, ad funded streams, and waiting moments, will see fierce demand and rising auction prices through 2030.
- Interruption becomes rational again only when the message value to the user approaches the displacement cost, which is a creative and targeting bar most campaigns cannot clear.
The Economics of a Broken Moment
Start with a first principles account. Every interruption is a forced trade: the advertiser takes seconds of the user's life and attention, and offers information in return. The trade nets out positive for the user only when the information's value exceeds the value of whatever was displaced. Feeds kept displacement value low. What was displaced was another piece of infinite content; the marginal scroll was nearly worthless to the scroller, which is precisely why they tolerated ads inside it.
Now watch what the post feed interfaces do to displacement value. A person mid question with an answer engine is doing directed cognitive work. A person reviewing what their agent bought is exercising judgment. A person inside a focused app session has a goal with a deadline. Interrupt any of these and you are not displacing idle scrolling; you are displacing intent. The trade that used to net out neutral now nets out sharply negative, and users respond the way anyone responds to a bad recurring trade: they restructure their lives to avoid the counterparty.
This is the mechanism behind trends people usually explain with vague talk about ad fatigue. It is not fatigue. It is pricing. Users are rationally refusing a trade that got worse.
The Displacement Price
Let me formalize it as the Displacement Price: the value of the user's interrupted activity, times the fraction of it your interruption destroys, plus the switching cost of recovering focus. You cannot read this number off a dashboard, but you can reason about its direction, and its direction is up.
Run an illustration, clearly labeled as one. Imagine a user's idle feed minute is worth a fraction of a cent to them, while a minute of directed task work is worth several cents to several dollars depending on stakes. Suppose post feed interfaces shift the average interrupted minute from mostly idle to mostly directed. Back of the napkin, the average Displacement Price of an impression rises by an order of magnitude even if ad load never changes. The advertiser's auction price did not move. The user's price exploded. That asymmetry cannot persist, because users hold the ultimate veto.
The veto arrives as what I call Interruption Debt: the accumulated avoidance infrastructure a user builds after repeated bad trades. Each intolerable ad does not just fail; it makes a small permanent contribution to the user installing a blocker, paying for an ad free tier, or delegating the whole task category to an agent that never sees ads at all. Interruption Debt is why interruptive media has a cost that outlives the campaign. You are not just buying impressions. You are selling, in tiny increments, your entire channel's future access. I covered the endgame of that debt spiral in the context of search in zero click searches: when the interface itself absorbs the answer, the interruptible surface simply disappears.
Where Interruption Still Clears
Honesty requires the other side of the ledger. There remain venues where displacement value is genuinely low, and in those venues interruption still clears economically. Waiting moments: queues, loading, transit. Ad funded entertainment where the viewer consciously trades attention for free content, a bargain I examine at length in Paper No.31. Live moments where the interruption is part of the cultural event. And the residual feeds, which shrink but do not vanish, populated by users who positively enjoy ambient browsing.
Here is the strategic problem: everyone's models will eventually discover the same shrinking set of low displacement venues, and auction dynamics will do what they always do. My falsifiable call: real prices for genuinely idle, genuinely human attention in these residual venues rise substantially faster than blended market CPMs between now and 2030. If cheap interruption stays cheap through 2030, this paper failed.
The other place interruption clears is when the message is so relevant that its value to the user rivals the displacement cost. A price alert on the flight you are actively tracking is technically an interruption; nobody experiences it as one. This is the narrow gate: interruption survives as a precision instrument for high value, high relevance moments, and dies as a bulk medium.
The Post Feed Buyer's Ledger
What should a buyer actually do with this? Build a second column in the media plan. The first column is what the impression costs you. The second column is your best estimate of what it costs the user. Where column two dwarfs column one, you are burning brand equity and stoking Interruption Debt to rent a metric. Where the columns are close, or column one exceeds column two because the venue is truly idle, interruption remains a legitimate buy.
This ledger also reframes creative. In a high displacement world, creative quality is not polish; it is compensation. The ad must pay the user back for the moment it took, with information, entertainment, or utility worth the theft. Most creative review processes evaluate whether an ad expresses the brand. Almost none evaluate whether it compensates the viewer. That is the review I would install.
And the ledger reframes intent capture. Demand that arrives through chosen channels, search, direct, answers, referrals, community, carries zero Displacement Price by definition: the user asked. The structural advantage of owning your search real estate is not just cheaper clicks. It is that every visit arrives debt free.
What I Would Do About It
Split your budget by displacement, not by channel. Classify every placement you buy into idle, mixed, and directed contexts, and demand a rising relevance bar as displacement rises. In directed contexts, either meet the precision gate, message value approaching displacement cost, or do not buy.
Cap and measure your Interruption Debt. Track leading indicators of avoidance in your own audience: blocker prevalence on your properties, opt outs, skip rates, paid tier migration among your customers. Treat a rise as a real cost of this quarter's media, because it is.
Overinvest in the debt free channels while they are still underpriced relative to their durability. Search authority, direct relationships, communities, and answer engine presence produce chosen attention, and chosen attention is about to be the only kind that gets cheaper with scale.
Rebuild creative review around compensation. One question in every review: what did we give the viewer in exchange for the moment we took? If the room cannot answer, the ad is not finished.
Finally, keep a small, disciplined interruption capability for the moments that clear the bar. The tool is not dead. The era of using it carelessly is. The advertisers who thrive after the feed will be the ones who interrupt rarely, precisely, and with something worth saying, and who let their competitors keep shouting into rooms where everyone has already learned to leave.