I worked for a few years at a company that provided a SaaS IVR product. Think call centre call routing, and PBX features on any dumb phone.
As people shy away from phone calls, and with the competition of VoIP, we gradually saw the erosion of the price per minute we could charge (roughly 40% drop over the course of 5 years).
The company tried to shift by looking at the data we had available. Millions of phone calls, and we knew exactly what kind of service was being called. Banks, airlines, airports, sex lines, restaurants, customer support, whatever. We could see when people called most, for how long, and we even knew which service inside the call centre they were talking to.
It wasn't long before the company wanted to exploit this, and they started working on the ability to play ads while people were waiting to get in touch with a service representative. Targeted ads.
Based on phone habits, we could tell whether the person calling was a stay-at-home parent, retiree, teen, young professional, etc. We could also tell their gender, in 60-70% of cases.
Because of the technology, we had access to actual phone number, even when people called with restricted identity. It's just how it works when you are registered as a "network operator".
This shift from "let's provide an amazing service" to "let's mine the crap out of everyone" definitely contributed in my leaving the company.