There is a point every publisher reaches where the ad stack is genuinely well run. Floors are tuned, the waterfall has been replaced by header bidding, viewability is healthy, and the next round of optimisation returns a rounding error. The instinct at that point is to push harder on the same levers. It rarely works, because the constraint is no longer efficiency — it is supply.
The alternative is to create impressions that did not previously exist. A user who taps into a quiz or a game session is generating attention that your article page was never going to capture. That session carries its own inventory, its own duration, and its own advertiser demand. Crucially, it is not taken from anywhere else in your stack.
This distinction matters commercially. A monetization partner that competes with your existing demand will show you a lift in their dashboard and a dip in someone else's. Net, you may have moved sideways. An additive layer is measurable in a much cleaner way: hold your existing revenue constant, and everything the new layer produces is genuinely new.
The practical test is simple. Ask any prospective partner whether their inventory bids against your current demand sources. If the answer involves the phrase "we optimise across", you are being sold a re-allocation, not an addition. If the inventory only exists because of a session your users would not otherwise have had, the maths is honest.
Integration friction is the second thing worth interrogating. A monetization layer that requires an SDK also requires a release cycle, a QA pass, and a dependency you now have to maintain. That is a real cost, and it is why so many additive revenue opportunities die in engineering backlog rather than in commercial negotiation. Link-based integrations sidestep the problem entirely.