“The impact that you can drive with notifications is reach times relevance times frequency. Not all notifications are equal and the really killer ones that are going to supercharge your business have high reach, high relevance and high frequency — and then you're in that golden quadrant.”

Notification impact = Reach × Relevance × Frequency (the RRF formula)

Distilled from SoundCloud's 500M-pushes-a-month system, the RRF formula scores every notification on three axes: reach (opt-in rate × addressable segment), relevance (proxy: CTR), and frequency (cadence before opt-outs). Boost relevance via personalization and you can push frequency higher without bleeding reach.