When revenue targets tighten, the quickest lever is usually another ad slot. It works for a while. Then session length drops, readers visit less often, the value of each impression falls and the page becomes slower. Ad density is one of the few decisions that affects revenue, experience and performance at the same time, so it deserves more thought than a quarterly push for extra inventory.
Think in sessions, not pageviews
Most density decisions are made per page: how many slots does this template have? Readers experience your site per session. A reader who reads four articles and watches a few clips sees every ad across all of them.
Measuring density per session changes the question from “can this page carry another ad?” to “what does a reader see across their whole visit, and does it make them want to come back?”
Signs your density is too high
- Session length falls after adding placements, even if revenue per page rises.
- Return visits decline over the following weeks.
- Viewability drops, because readers scroll faster past pages crowded with ads.
- Page performance suffers, with slower loading and layout shifts.
- Prices soften, as buyers notice lower attention and more cluttered environments.
Any one of these can have other causes. Several together usually point to density.
A better way to find the balance
Start from the reader’s journey
Map what a typical session looks like: which pages, which modules, which videos. Mark every ad the reader encounters. The picture is often more crowded than anyone intended.
Prioritise high-attention placements
One ad the reader actually sees is worth more than three they scroll past. Formats that live inside the experience, such as a sponsored story in a vertical feed or a unit in the player that does not interrupt the content, tend to earn more attention than extra slots in the sidebar.
Cap frequency across the session
Set limits on how often the same reader sees ads of a given type, and on how often the same advertiser appears. In video, cap the ratio of ads to content clips rather than letting demand decide.
Test with holdouts
Run a controlled test: keep a share of readers on a lighter ad layout for several weeks and compare revenue per reader, session length and return rate. Short tests flatter heavy layouts, because the cost in lost return visits takes time to appear.
Video changes the arithmetic
In a vertical video feed, ads arrive between clips. The more clips a reader watches, the more ad opportunities there are, without adding a single slot to the page. That means the best way to grow video revenue is usually to improve the content and the entry points, so readers watch longer, rather than to raise the ad ratio.
It also makes the ratio itself an important setting. A feed with an ad after every clip may look good for a day and then lose its audience. A feed with a sensible ratio keeps readers swiping.
What we recommend
- Measure density per session.
- Favour fewer, higher-attention placements.
- Cap frequency by format and advertiser.
- Test changes over weeks, with a holdout.
- Grow video revenue through engagement, not ad frequency.
Publishers control how many formats run in our vertical player, where they appear and how often. The right setting is the one that keeps readers coming back.
