Growth-service vs organic: the 90-day reach decay

Growth-service vs organic: the 90-day reach decay
n=36 accounts, tracked from service-start through day 90.
— Engagement-service accounts: +2,400 median followers, reach rate fell from 21% to 11%
— Matched organic cohort: +610 followers, reach rate held at 20%
Services add followers faster but dilute the ratio with low-intent accounts, halving distribution. The follower count went up while actual humans-reached-per-post went down.
So what: more followers is the wrong metric. Reach-per-post is the budget. A service that triples your count and halves your reach rate left you with fewer real impressions and a worse signal.