Good question. According to Venture Beat they have their SDK installed in top 100 apps in 2018.

https://venturebeat.com/2018/10/24/placer-ai-raises-4-millio...

So then through app publishers, either intentionally or through an SDK dependency that they are unaware of. I wonder how app revenue sources is evolving over time. Could it be that "data monetization" is one the rise with the proliferation of startups like this one?