I'm not sure what you mean by this because Nielsen absolutely targets children. The parents are explicitly consenting to having the box in the home but the box is constantly monitoring what is on the TV and invasively forces you tell it every 30 minutes or so exactly who is watching the screen.
My family was a Nielsen family for a time when I was in college and my 8-12 year old brothers were living at home.
Nielsen asks the parents to consent to monitoring. The parents are adults, and adults are in a position to be able to give such consent. Parents routinely make decisions for their children that the children are not in a position to make on their own. This ensures that children, who do not have the education and life experience to be able to make such decisions on their own, have their interests looked out for by responsible adults.
Facebook skipped the parents and pitched their app to the kids directly.
There is no invasion like what you're mentioning in the (recently) current systems. I was a Nielsen household. They use audio tracking via HDMI/optical audio to "see" what's being watched, and they can of course tell what TV it's coming from, but that's the extent of it.
I'm not sure what you mean by this because Nielsen absolutely targets children. The parents are explicitly consenting to having the box in the home but the box is constantly monitoring what is on the TV and invasively forces you tell it every 30 minutes or so exactly who is watching the screen.
My family was a Nielsen family for a time when I was in college and my 8-12 year old brothers were living at home.