“In January, the cost per thousand impressions for an Instagram Stories ad was $4.62, while the interaction rate was 1 percent. For the 30 days to Aug. 16, the CPM for Instagram Stories was $5.53, while the interaction rate was 0.47 percent. The story here is that when a new placement shows up, people interact with ads more because it’s new and there’s less of a choice. As feeds and stories fill up with ads, people become less reactive to them.”