Interesting article about PPM's (personal people meters) and how they have shaken-up the radio industry.
https://www.bloomberg.com/features/2016-delilah/
I were a meter for a time, I think it was just a test they were doing. I'm in a pretty rural area so I don't know that they use them at all in this market. I listen to a pretty eclectic mix; it did do my heart good to think that I might be boosting the ratings for a tiny daytime-only AM station, or something like that. The trouble with any ratings system like that is it's a real pain in the neck to deal with on a day-to-day basis, and you won't exactly get rich doing it.